Source guide for CalculatorShelf units and formulas

Storage calculators

RAID, disk-capacity, binary/decimal unit, transfer-rate, surveillance-storage, memory-card, and VRAM tools use deterministic arithmetic plus storage-industry terminology checks. Binary-vs-decimal unit conversions are called out where they change the answer.

Home-project calculators

Home-project pages are estimating aids. Material formulas use visible geometric assumptions; cost and safety-sensitive pages remain planning aid unless current product data, code constraints, and professional boundaries are clear.

Pool and water calculators

Pool and chemical pages are conservative planning aids. Product labels, test-kit readings, local codes, and qualified pool guidance override every default. Safety-sensitive pages stay conservative until label constants are clear.

Shipping calculators

Shipping pages expose dimensional, weight, mileage, and fee assumptions rather than claiming live quotes. Real carrier tariffs, customs requirements, fuel surcharges, seasonality, and provider quotes can override defaults.

Lifestyle calculators

Household pages use simple area, count, or sizing heuristics. They are written to make the assumption visible instead of implying exact fit, exact weather, or exact product performance.

Sports calculators

Running pace tools use official road-race distance constants for common events and simple time-divided-by-distance arithmetic. See World Athletics marathon distance, World Athletics half marathon distance, and NIST SI length units.

Sports sizing tools are starting-point aids. Manufacturer size charts, terrain, skill level, and personal fit checks override generalized formulas.

Business calculators

Business calculators use entered prices, costs and quantities. Check the formula-specific sources below alongside the assumptions on each tool.

How to check a source

Check that the cited reference applies to your units, product and scenario. Compare the formula and worked example before using the result.

Safety-sensitive calculators use conservative language and point users back to product labels, qualified professionals, local code, or authoritative references when a generic web calculation should not be the final decision.

Rocket equation and standard gravity

These references support the named formula, unit relationship, or decision boundary. Calculator inputs remain visible so a reader can replace every example assumption.

• NASA Glenn ideal rocket equation
• NIST CODATA standard gravity

GPA and course weighting

These references support the named formula, unit relationship, or decision boundary. Calculator inputs remain visible so a reader can replace every example assumption.

• College Board 4.0-scale GPA method
• College Board weighted and unweighted GPA guidance

Pallet volume and unit conversion

These references support the named formula, unit relationship, or decision boundary. Calculator inputs remain visible so a reader can replace every example assumption.

• NIST SI length units
• CalculatorShelf pallet volume formula and limits

Translation purchasing and entered pricing terms

These references support the named formula, unit relationship, or decision boundary. Calculator inputs remain visible so a reader can replace every example assumption.

• Institute of Translation and Interpreting client guide
• CalculatorShelf translation cost formula and limits

Electricity use and lighting cost

These references support the named formula, unit relationship, or decision boundary. Calculator inputs remain visible so a reader can replace every example assumption.

• U.S. EIA electricity measurement guide
• CalculatorShelf lighting energy formula and limits

Sources used by these calculators

These source notes explain which formulas, units, assumptions, and safety guidance inform each calculator. They show what each source covers and which calculators link to it; entered values and site estimates are labeled on the calculator pages.

• SI Units – Temperature — National Institute of Standards and Technology. Exact Celsius, Fahrenheit and kelvin relationships and absolute zero Evidence: government_source. Reviewed: 2026-08-30. Used by: Unit Converter Unit conversion: Temperature points use scale offsets; absolute zero is 0 K, equivalent to −273.15 °C and −459.67 °F..
• Metric (SI) prefixes — National Institute of Standards and Technology. SI decimal prefixes and unit terminology Evidence: government_source. Reviewed: 2026-08-30. Supports: Decimal SI-prefix unit conversion kilo, mega, and giga decimal multipliers use powers of 1000 Keep decimal TB/GB labels distinct from binary TiB/GiB labels. Used by: RAID Calculator Unit conversion: TB/GB and TiB/GiB labels use distinct decimal and binary prefixes.; RAID 5 Capacity Calculator Unit conversion: Decimal and binary capacity labels.; RAID 6 Calculator Unit conversion: Decimal and binary capacity labels.; RAID 10 Calculator Unit conversion: Decimal and binary capacity labels.; Unit Converter Unit conversion: SI decimal prefixes and labels remain distinct..
• SNIA Dictionary — Storage Networking Industry Association. Storage and RAID terminology Evidence: professional_body. Reviewed: 2026-08-30. Supports: Explain RAID capacity separately from backup and rebuild reliability. Used by: RAID Calculator Terminology: RAID and storage terms are defined consistently with storage-industry terminology.; RAID 5 Capacity Calculator Terminology: RAID 5 and parity terminology.; RAID 6 Calculator Terminology: RAID 6 and dual-parity terminology.; RAID 10 Calculator Terminology: RAID 10 and mirror terminology.; Mixed Drive RAID Calculator Terminology: Mixed-drive RAID and smallest-drive terminology.; Windows Storage Spaces Planning Guide Terminology: Storage resiliency terminology..
• Recommendation ITU-R P.525: Calculation of free-space attenuation — International Telecommunication Union. Free-space path-loss identity Evidence: official_standard. Reviewed: 2026-08-30. Supports: Free-space path-loss identity Use only within the ideal line-of-sight model stated on the calculator Do not present a free-space estimate as a site survey or link guarantee. Used by: RF Path Planning Guide Formula: ITU-R P.525 supports the stated ideal free-space attenuation model..
• Ideal rocket equation — NASA Glenn Research Center. Tsiolkovsky ideal delta-v relationship Evidence: government_source. Reviewed: 2026-08-30. Supports: Ideal rocket equation Specific impulse and standard gravity are inputs or declared constants Wet mass must exceed dry mass Ideal delta-v is not a launch or vehicle-performance guarantee. Used by: Rocket Equation Calculator Formula: NASA’s ideal rocket equation relationship supports the displayed delta-v method..
• Pool chemical safety — Centers for Disease Control and Prevention. Pool chemical handling boundary Evidence: government_source. Reviewed: 2026-08-30. Supports: Follow chemical-label handling, storage, and emergency guidance. Used by: Pool Chemical Planning Guide Safety guidance: Follow safe chemical handling, storage, and emergency instructions.; Chlorine Planning Guide Safety guidance: Follow safe chemical handling and test-again boundaries.; Pool pH Planning Guide Safety guidance: Chemical handling and test-again boundary.; Pool Alkalinity Planning Guide Safety guidance: Chemical handling and test-again boundary.; Pool Stabilizer Planning Guide Safety guidance: Chemical handling and test-again boundary.; Saltwater Pool Planning Guide Safety guidance: Chemical handling and test-again boundary.; Pool Water Balance Planning Guide Safety guidance: Chemical handling and test-again boundary.; Aquarium Ammonia Planning Guide Safety guidance: Chemical and water-safety decisions require conservative action..
• Pesticide labels — U.S. Environmental Protection Agency. Product-label-first decision boundary Evidence: government_source. Reviewed: 2026-08-30. Supports: The product label controls any chemical dose or use instruction. Used by: Pool Chemical Planning Guide Use boundary: Product labeling controls chemical use and dose instructions.; Chlorine Planning Guide Use boundary: Product labels control actual dosing.; Chemical Dosing Planning Guide Use boundary: Product labels control actual dosing..
• Protect your move — Federal Motor Carrier Safety Administration. Consumer auto-transport and moving guidance Evidence: government_source. Reviewed: 2026-08-30. Supports: A planning estimate is not a carrier quote or contract. Used by: Car Shipping Calculator Use boundary: Confirm carrier, insurance, terms, and final quote independently..
• Use of electricity — U.S. Energy Information Administration. Electricity-use terminology; not a current local price Evidence: government_source. Reviewed: 2026-08-30. Supports: Electricity price remains user-entered and local; it is not supplied by this source. Used by: Christmas Light Energy Cost Calculator Terminology: Electricity-use terminology; price remains an entered local value..
• Construction industry safety and health — Occupational Safety and Health Administration. Construction and installation safety boundary Evidence: government_source. Reviewed: 2026-08-30. Supports: Structural, electrical, and construction work requires applicable code and qualified review. Used by: Cable Planning Guide Safety guidance: Electrical work and code compliance require qualified review.; Solar Panel Roof Load Planning Guide Safety guidance: A structural reviewer must confirm roof capacity and applicable safety requirements.; Stair Stringer Planning Guide Safety guidance: Construction safety and local code review remain outside the calculator.; Trailer Ramp Planning Guide Safety guidance: Loading safety, traction, and load rating require real equipment review..
• Laboratory safety: cryogens and dry ice — Occupational Safety and Health Administration. Dry-ice handling, ventilation, protective equipment, and sealed-container safety boundary Evidence: government_source. Reviewed: 2026-08-30. Supports: Use protective equipment, ventilation, and pressure-safe containers when handling dry ice. Used by: Dry Ice Planning Guide Safety guidance: Use dry-ice-specific ventilation, protective-equipment, and pressure-safe-container guidance..
• Runoff and the water cycle — U.S. Geological Survey. Runoff terminology; coefficient remains user-entered Evidence: government_source. Reviewed: 2026-08-30. Supports: Runoff coefficient remains an entered modeling assumption between 0 and 1 A simple runoff estimate is not a drainage design. Used by: Stormwater Calculator Terminology: Runoff and impervious-surface terminology..
• Competition and technical rules — World Athletics. Running-distance context; pace arithmetic is mathematical identity Evidence: professional_body. Reviewed: 2026-08-30. Supports: Common road-race distances are named inputs or presets Race projections are pace arithmetic, not a performance prediction. Used by: Run Race Pace Calculator Terminology: Race-distance names and context..
• Frankfurter currency data API — Frankfurter. No-key exchange-rate API transport with provider filtering and dated responses Evidence: open_data_api. Reviewed: 2026-08-30. Supports: A response must identify base, quote, positive rate, and ISO date The API transports reference data and does not quote a consumer transaction. Used by: Currency Converter Reference data: Frankfurter provides the no-key API transport and rate date..
• Euro foreign exchange reference rates — European Central Bank. Informational foreign-exchange reference rates, not transaction prices Evidence: government_source. Reviewed: 2026-08-30. Supports: Reference rates are informational and should not be presented as transaction rates. Used by: Currency Converter Reference data: ECB reference rates are informational and are not transaction quotes..
• Regulation Z — Truth in Lending — Consumer Financial Protection Bureau. Boundary for APR, credit advertising, estimates, and mortgage disclosures Evidence: government_source. Reviewed: 2026-08-30. Supports: A planning result is not an APR determination, lender quote, Loan Estimate, Closing Disclosure, or advertising compliance decision. Used by: Mortgage Calculator: Payments & Amortization Use boundary: A planning calculator is not a lender APR, Loan Estimate, quote, or required disclosure..
• Mathematical identities and dimensional analysis — CalculatorShelf. Arithmetic, geometry, percentage, rate, and unit-conversion identities Evidence: mathematical_identity. Reviewed: 2026-08-30. Supports: Arithmetic, geometry, percentage, rate, and unit-conversion identities Use the page-specific limitations before treating a formula result as a decision. Used by: RAID Calculator Formula: Equal-drive RAID capacity uses the selected layout reserve and active drive count.; RAID 5 Capacity Calculator Formula: RAID 5 reserves one active-drive equivalent for parity.; RAID 6 Calculator Formula: RAID 6 reserves two active-drive equivalents for parity.; RAID 10 Calculator Formula: RAID 10 uses complete mirror pairs for usable capacity.; Mixed Drive RAID Calculator Formula: The planning model applies the smallest entered drive size to each array position.; NAS Capacity Calculator Formula: Apply the selected RAID reserve and entered storage allowance before comparing the target; layout minimums apply to active drives.; CCTV / Surveillance Storage Calculator Formula: Bitrate, cameras, recorded time, motion share, and retention days determine byte volume.; CCTV Storage Calculator Formula: Bitrate, cameras, recorded time, motion share, and retention days determine byte volume.; Memory Card Calculator Formula: Decimal usable GB after the entered reserve is divided by average MB per photo or converted to bits and divided by encoded Mbps; whole photo capacity rounds down.; Download Time Calculator Formula: Elapsed time is file bits divided by effective throughput.; Memory Timing Calculator Formula: True latency equals cycles × 2000 ÷ MT/s.; Cable Planning Guide Formula: Voltage drop is estimated from resistance, current, length, and phase path.; VRAM Calculator Formula: Stored weights use parameters × bits/8 bytes, converted to GiB by 2^30.; RF Path Planning Guide Formula: The free-space path-loss equation is applied to frequency and distance.; Windows Storage Spaces Planning Guide Formula: The simplified two-way, three-way, or parity reserve is applied to raw capacity.; Roof Area Calculator Formula: Footprint and pitch produce a sloped-area estimate.; Flat Roofing Cost Planning Guide Formula: Footprint plus waste is multiplied by the low and high per-square-foot inputs.; Stump Grinding Cost Planning Guide Formula: Diameter and count form a base cost, multipliers model access and roots, and debris is added separately.; House Addition Planning Guide Formula: Area is multiplied by the entered base rate and multipliers, then low/mid/high planning factors are applied.; Loft Conversion Cost Planning Guide Formula: Area times rate and project multipliers forms a mid estimate; fixed low/high factors create a planning range.; Blown Cellulose Insulation Calculator Formula: Added R = max(0, target R − existing R). If added R is zero, bags are zero; otherwise bags = ceiling(area/entered coverage at that added R), with exact decimal inputs before whole-bag rounding.; Solar Panel Planning Guide Formula: Monthly energy is converted to daily demand and divided by sun hours and a loss-adjusted panel output.; Solar Panel Roof Load Planning Guide Formula: Panel and hardware weight divided by roof area gives an added-load screen.; Stormwater Calculator Formula: Impervious area × rainfall × coefficient is converted to volume.; Rhino Board Ceiling Calculator Formula: Room area is increased by waste and divided by coverage per board, then rounded up.; Pipe Offset Calculator Formula: Sine and tangent identities calculate travel and setback.; Wire Mesh Calculator Formula: Area plus waste is divided by the entered sheet/roll coverage and rounded up.; Brick Walkway Calculator Formula: Walkway area plus waste is divided by brick coverage and rounded up.; Stair Stringer Planning Guide Formula: Riser count, run, and stringer length use the displayed geometry.; Pool Chemical Planning Guide Formula: The displayed chlorine basis scales by volume, ppm change, and strength.; Pool Volume Calculator Formula: Shape-specific surface area times average depth is converted from cubic feet to gallons.; Chlorine Planning Guide Formula: The displayed chlorine basis scales by volume, ppm change, and strength.; Pool pH Planning Guide Formula: The page compares current and target pH without claiming a universal dose.; Pool Alkalinity Planning Guide Formula: Volume, ppm change, and entered product factor determine the estimate.; Pool Stabilizer Planning Guide Formula: Volume, ppm change, and entered product factor determine the estimate.; Saltwater Pool Planning Guide Formula: Volume, ppm change, and entered product factor determine the estimate.; Pool Water Balance Planning Guide Formula: The displayed score compares entered readings with visible planning bands.; Chemical Dosing Planning Guide Formula: Volume, ppm change, and entered product factor determine the estimate.; Aquarium Ammonia Planning Guide Formula: A pH-dependent fraction of total ammonia is estimated.; Car Shipping Calculator Formula: Distance, entered rate, adjustments, and uncertainty band produce the planning range.; LCL Shipping Calculator Formula: Package dimensions and weight proxy produce a planning chargeable measure.; Pallet Calculator Formula: Two whole-box footprint grids are compared before height and load-weight limits cap the count.; Warehouse Storage Cost Calculator Formula: Pallet-days, handling, and pick fees are added.; Trailer Ramp Planning Guide Formula: Arctangent and tangent calculate angle and required length.; Wrapping Paper Calculator Formula: Two cut orientations are compared with roll width and length.; Pinhole Camera Exposure Calculator Formula: Pinhole f-number and square-law exposure scaling are applied to a reference exposure.; Necktie Length Planning Guide Formula: No universal height/neck-to-tie-length equation is published. This is a measurement and fit preparation guide with no interactive numerical result.; Dry Ice Planning Guide Formula: Cooler size, duration, insulation, and use factors form the estimate.; Snow Day Planning Guide Formula: Snow, temperature, ice, wind, and strictness receive visible weights and the score is bounded.; Run Race Pace Calculator Formula: Elapsed seconds divided by distance gives pace and projection.; Hang Time Calculator Formula: Ideal same-height projectile equations convert airtime and speed.; Cross Country Ski Size Calculator Unit conversion: One inch is 2.54 centimeters.; Reverse Margin Calculator Formula: Gross margin, markup, and solved price/cost use standard arithmetic identities.; System of Equations Calculator Formula: Partial-pivot Gaussian elimination classifies and solves the entered system.; Rocket Equation Calculator Formula: Mass ratio and propellant fraction are derived arithmetically.; Homeschool GPA Calculator Formula: Credit-weighted quality points are divided by total credit.; Pallet Volume Calculator Formula: Loaded dimensions and pallet count are converted to cubic feet and meters.; Translation Cost Calculator Formula: Word cost, minimum, fees, and discount are combined arithmetically.; Christmas Light Energy Cost Calculator Formula: Power × time gives kWh; kWh × entered price gives cost.; Basic Calculator Formula: The selected arithmetic and percentage operation is applied directly.; Scientific Calculator Formula: Declared functions and precedence are evaluated by a bounded local parser.; Unit Converter Formula: Compatible quantities convert through declared base-unit factors.; Date Calculator Formula: UTC-normalized civil dates support whole calendar-day comparison and addition.; Currency Converter Formula: Amount multiplied by the displayed rate produces the conversion.; Tip & Split Bill Calculator Formula: Tip percentage and division across people use declared arithmetic.; Shopping Discount Calculator Formula: Each percentage applies sequentially before the fixed coupon and entered tax.; Mortgage Calculator: Payments & Amortization Formula: The fixed-rate payment identity and month-by-month balance schedule determine results.; Percentage Change Calculator Formula: Absolute change, denominator-specific percentage change, multiplier, and recovery arithmetic are applied directly.; Mean, Median, Mode & Range Calculator Formula: Mean, median, mode, range, and population/sample standard deviation use the declared list identities.; Dimensional Weight Calculator Formula: Entered package dimensions are multiplied and divided by the entered carrier divisor before the selected rounding and actual-weight comparison.; Break-Even Point Calculator Formula: Contribution margin divides fixed cost and fixed cost plus target profit to determine whole-unit thresholds.; Battery & UPS Runtime Calculator Formula: Delivered watt-hours divided by adjusted watt load produces the runtime estimate.; Swim Pace Calculator Formula: Elapsed time divided by distance produces pace; declared yard, meter, and course-length conversions produce speed and pool lengths.; CTR Calculator Formula: CTR (%) = clicks ÷ impressions × 100. Use counts from the same reporting period and reporting system. Small nonzero rates use scientific notation: 1e-10% means 0.0000000001%.; CPC Calculator Formula: Average CPC = total click spend ÷ recorded paid clicks. Display rounds to cents; calculations retain the unrounded quotient.; Blended Hourly Rate Calculator Formula: Blended USD/hour = Σ(hours × USD/hour) ÷ Σ(hours). Total entered bill = Σ(hours × rate). Zero-hour rows contribute nothing. Aggregate unrounded products before rounding the final display to cents; separately rounded rows can differ by a cent from that aggregate. This is not an invoicing ledger.; 3D Printing Cost Calculator Formula: Material = grams/1000 × USD/kg × (1 + waste/100). Energy = machine hours × watts/1000 × USD/kWh. Depreciation = hours × (purchase − residual)/productive lifetime hours. Labor = minutes/60 × hourly rate. Cost = material + energy + depreciation + labor + other cost. Price = cost × (1 + markup/100).; Rent Split Calculator Formula: For n active roommates, share = rent × [common%/100 ÷ n + (1 − common%/100) × room weight/total room weight]. Set common share to 100% for an equal split, or 0% for room-weight-only. Enter rent in whole cents, floor raw allocations, then distribute remaining cents to the largest fractional remainders; ties use row order.; Safety Stock Calculator Formula: Daily observations are nonnegative quantities over one complete day, and L is a nonnegative integer count of complete daily periods. A fractional mean E[L] is allowed only with enough lead-time variance to be possible for integer L; fixed lead time must be whole days. Lead-time demand variance = E[L] × σd² + μd² × σL², derived by conditional variance for independent daily demand and independent lead time. Safety stock = z × √variance, rounded up to whole units. Reorder point = ceiling(mean daily demand × mean lead days + whole safety stock). Fixed lead time has σL = 0. For fractional mean a + f, the entered lead-time variance must be at least f × (1 − f). This model does not interpolate part of a day.; Billable Hours Calculator Formula: Available hours = workdays × hours per day. Billable hours = available − nonbillable hours. Utilization (%) = billable/available × 100; zero available hours has no defined utilization. Entered bill value = billable hours × entered rate.; Invoice Due Date Calculator Formula: Unadjusted due date = invoice date + entered calendar days; the invoice date is day zero. Optional weekend adjustment moves only Saturday or Sunday forward to Monday or backward to Friday. Calendar arithmetic uses UTC day boundaries to avoid daylight-saving shifts.; Weighted Average Interest Rate Calculator Formula: Weighted nominal annual rate (%) = Σ(principal × annual rate %) ÷ Σ(principal). Simple annual interest illustration = Σ(principal × rate/100), assuming all balances stay constant for one year. Aggregate unrounded products before rounding the final illustration to cents.; DPMO Calculator Formula: Total opportunities = inspected units × defined opportunities per unit. DPO = observed defects/total opportunities. DPMO = DPO × 1,000,000. DPU = observed defects/inspected units. Small nonzero metrics use scientific notation: 1e-9 is 0.000000001.; Siding Material Calculator Formula: Rectangular wall area = width × height; triangular gable area = base × height/2. Gross area = entered wall area + entered gable area. Net coverage = gross − excluded openings. Ordering coverage = net × (1 + waste/100). Whole packages = ceiling(ordering coverage/installed coverage per package), using decimal input arithmetic before whole-unit rounding. Display rounding never changes the package count. Material cost = whole packages × entered package price..
• User-entered values — CalculatorShelf. Values supplied by the visitor, including prices, dimensions, rates, and test readings Evidence: user_entered_value. Reviewed: 2026-08-30. Supports: Visitor-entered measurements, prices, rates, and readings are used as entered; confirm them before relying on the result. Used by: RAID Calculator Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; RAID 5 Capacity Calculator Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; RAID 6 Calculator Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; RAID 10 Calculator Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; Mixed Drive RAID Calculator Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; NAS Capacity Calculator Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; CCTV / Surveillance Storage Calculator Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; CCTV Storage Calculator Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; Memory Card Calculator Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; Download Time Calculator Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; Memory Timing Calculator Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; Cable Planning Guide Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; VRAM Calculator Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; RF Path Planning Guide Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; Windows Storage Spaces Planning Guide Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; Linux Chmod Calculator Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; Roof Area Calculator Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; Flat Roofing Cost Planning Guide Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; Stump Grinding Cost Planning Guide Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; House Addition Planning Guide Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; Loft Conversion Cost Planning Guide Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; Blown Cellulose Insulation Calculator Visitor input: Use product coverage per bag for the added R-value and required settled depth.; Blown Cellulose Insulation Calculator Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; Solar Panel Planning Guide Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; Solar Panel Roof Load Planning Guide Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; Stormwater Calculator Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; Rhino Board Ceiling Calculator Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; Pipe Offset Calculator Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; Wire Mesh Calculator Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; Brick Walkway Calculator Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; Stair Stringer Planning Guide Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; Pool Chemical Planning Guide Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; Pool Volume Calculator Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; Chlorine Planning Guide Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; Pool pH Planning Guide Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; Pool Alkalinity Planning Guide Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; Pool Stabilizer Planning Guide Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; Saltwater Pool Planning Guide Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; Pool Water Balance Planning Guide Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; Chemical Dosing Planning Guide Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; Aquarium Ammonia Planning Guide Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; Car Shipping Calculator Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; LCL Shipping Calculator Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; Pallet Calculator Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; Warehouse Storage Cost Calculator Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; Trailer Ramp Planning Guide Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; Wrapping Paper Calculator Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; Pinhole Camera Exposure Calculator Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; Necktie Length Planning Guide Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; Dry Ice Planning Guide Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; Snow Day Planning Guide Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; Run Race Pace Calculator Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; Hang Time Calculator Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; Cross Country Ski Size Calculator Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; Reverse Margin Calculator Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; System of Equations Calculator Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; Rocket Equation Calculator Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; Homeschool GPA Calculator Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; Pallet Volume Calculator Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; Translation Cost Calculator Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; Christmas Light Energy Cost Calculator Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; Basic Calculator Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; Scientific Calculator Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; Unit Converter Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; Date Calculator Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; Currency Converter Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; Tip & Split Bill Calculator Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; Shopping Discount Calculator Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; Mortgage Calculator: Payments & Amortization Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; Percentage Change Calculator Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; Mean, Median, Mode & Range Calculator Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; Dimensional Weight Calculator Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; Break-Even Point Calculator Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; Battery & UPS Runtime Calculator Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; Swim Pace Calculator Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; CTR Calculator Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; CPC Calculator Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; Blended Hourly Rate Calculator Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; 3D Printing Cost Calculator Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; Rent Split Calculator Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; Safety Stock Calculator Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; Billable Hours Calculator Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; Invoice Due Date Calculator Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; Weighted Average Interest Rate Calculator Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; DPMO Calculator Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor.; Siding Material Calculator Visitor input: Measurements, prices, readings, and workload selections are supplied by the visitor..
• Example defaults — CalculatorShelf. Illustrative server-rendered values, not current market claims Evidence: example_default. Reviewed: 2026-08-30. Supports: Defaults illustrate a worked scenario and are not universal recommendations. Used by: RAID Calculator Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; RAID 5 Capacity Calculator Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; RAID 6 Calculator Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; RAID 10 Calculator Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; Mixed Drive RAID Calculator Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; NAS Capacity Calculator Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; CCTV / Surveillance Storage Calculator Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; CCTV Storage Calculator Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; Memory Card Calculator Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; Download Time Calculator Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; Memory Timing Calculator Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; Cable Planning Guide Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; VRAM Calculator Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; RF Path Planning Guide Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; Windows Storage Spaces Planning Guide Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; Linux Chmod Calculator Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; Roof Area Calculator Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; Flat Roofing Cost Planning Guide Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; Stump Grinding Cost Planning Guide Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; House Addition Planning Guide Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; Loft Conversion Cost Planning Guide Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; Blown Cellulose Insulation Calculator Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; Solar Panel Planning Guide Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; Solar Panel Roof Load Planning Guide Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; Stormwater Calculator Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; Rhino Board Ceiling Calculator Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; Pipe Offset Calculator Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; Wire Mesh Calculator Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; Brick Walkway Calculator Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; Stair Stringer Planning Guide Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; Pool Chemical Planning Guide Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; Pool Volume Calculator Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; Chlorine Planning Guide Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; Pool pH Planning Guide Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; Pool Alkalinity Planning Guide Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; Pool Stabilizer Planning Guide Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; Saltwater Pool Planning Guide Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; Pool Water Balance Planning Guide Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; Chemical Dosing Planning Guide Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; Aquarium Ammonia Planning Guide Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; Car Shipping Calculator Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; LCL Shipping Calculator Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; Pallet Calculator Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; Warehouse Storage Cost Calculator Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; Trailer Ramp Planning Guide Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; Wrapping Paper Calculator Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; Pinhole Camera Exposure Calculator Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; Necktie Length Planning Guide Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; Dry Ice Planning Guide Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; Snow Day Planning Guide Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; Run Race Pace Calculator Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; Hang Time Calculator Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; Cross Country Ski Size Calculator Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; Reverse Margin Calculator Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; System of Equations Calculator Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; Rocket Equation Calculator Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; Homeschool GPA Calculator Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; Pallet Volume Calculator Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; Translation Cost Calculator Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; Christmas Light Energy Cost Calculator Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; Basic Calculator Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; Scientific Calculator Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; Unit Converter Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; Date Calculator Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; Currency Converter Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; Tip & Split Bill Calculator Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; Shopping Discount Calculator Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; Mortgage Calculator: Payments & Amortization Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; Percentage Change Calculator Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; Mean, Median, Mode & Range Calculator Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; Dimensional Weight Calculator Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; Break-Even Point Calculator Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; Battery & UPS Runtime Calculator Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; Swim Pace Calculator Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; CTR Calculator Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; CPC Calculator Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; Blended Hourly Rate Calculator Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; 3D Printing Cost Calculator Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; Rent Split Calculator Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; Safety Stock Calculator Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; Billable Hours Calculator Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; Invoice Due Date Calculator Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; Weighted Average Interest Rate Calculator Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; DPMO Calculator Example setup: The published default is an illustrative worked scenario, not a universal recommendation.; Siding Material Calculator Example setup: The published default is an illustrative worked scenario, not a universal recommendation..
• Interest rate and APR describe different costs — Consumer Financial Protection Bureau. Nominal interest versus APR boundary only, not loan consolidation pricing Evidence: government_source. Reviewed: 2026-10-05. Supports: Nominal interest versus APR boundary only, not loan consolidation pricing. Used by: Weighted Average Interest Rate Calculator Use boundary: CFPB explains that APR includes costs beyond the nominal interest rate; this tool only combines entered nominal rates..
• Coreutils manual: Numeric Modes — GNU / Free Software Foundation. Unix permission bit and octal triplet mapping; local GNU manual version 9.7 was inspected because web retrieval timed out Evidence: manufacturer_documentation. Reviewed: 2026-10-05. Supports: Unix permission bit and octal triplet mapping; local GNU manual version 9.7 was inspected because web retrieval timed out. Used by: Linux Chmod Calculator Manufacturer guidance: Read, write and execute/search use three bits represented as an octal triplet for owner, group and others..
• Clickthrough rate (CTR): Definition — Google. CTR metric definition, not performance benchmarks Evidence: manufacturer_documentation. Reviewed: 2026-10-05. Supports: CTR = clicks/impressions CTR metric definition, not performance benchmarks. Used by: CTR Calculator Formula: Google Ads defines CTR as recorded clicks divided by impressions..
• Average cost-per-click (Avg. CPC): Definition — Google. Average actual CPC definition and distinction from maximum bid Evidence: manufacturer_documentation. Reviewed: 2026-10-05. Supports: Average CPC = total click spend/clicks Average actual CPC definition and distinction from maximum bid. Used by: CPC Calculator Formula: Google Ads defines average CPC as total cost of clicks divided by the click count..
• Normal distribution — National Institute of Standards and Technology. Normal model and quantile definition, not validation of actual inventory demand Evidence: government_source. Reviewed: 2026-10-05. Supports: Normal distribution and standard normal quantile Normal model and quantile definition, not validation of actual inventory demand. Used by: Safety Stock Calculator Formula: Normal distribution and quantiles support the declared z interpretation; the lead-time variance is derived on this page..
• DPMO: incoming inspection and process performance limits — American Society for Quality. DPMO sample/process interpretation boundary; not a sigma conversion Evidence: professional_body. Reviewed: 2026-10-05. Supports: DPMO sample/process interpretation boundary; not a sigma conversion. Used by: DPMO Calculator Use boundary: ASQ explains the limits of incoming inspection and why it does not establish supplier process sigma..
• Beginner’s Guide: Choosing Cross Country Skis — Salomon. General height starting ranges; weight and product-specific flex chart override them Evidence: manufacturer_documentation. Reviewed: 2026-10-05. Supports: Classic height +20 to +30 cm; skate +10 to +15 cm starting context General height starting ranges; weight and product-specific flex chart override them. Used by: Cross Country Ski Size Calculator Manufacturer guidance: Convert inches to cm; Salomon gives general height context of height plus 20–30 cm for classic or 10–15 cm for skate. No generic backcountry range is provided..

Download source data: source-guide.json.