System of Equations Calculator
Solve 2x2 or 3x3 systems of linear equations with Gaussian elimination, solution type, determinant, residual, and clear limits.
Interactive calculatorOpen calculatorMath & Education Calculators
41 interactive calculators · 0 planning guides
Calculate arithmetic, scientific expressions, units, dates, algebra, physics, and education formulas with visible methods.
Available calculators
Choose a focused tool, keep the method and units visible, and compare scenarios without sending deterministic inputs to a calculation server.
Rocket Equation Calculator
Calculate ideal rocket delta-v from wet mass, dry mass, and specific impulse. See mass ratio, propellant fraction, exhaust velocity, formula, and limits.
Interactive calculatorOpen calculatorHomeschool GPA Calculator
Calculate credit-weighted homeschool GPA with entered 0–4 grade points and optional honors or advanced-course weight. See quality points and transcript cautions.
Interactive calculatorOpen calculatorBasic Calculator
Calculate arithmetic, percentages, percent change, division, and powers with a clear operation label and keyboard-friendly inputs.
Interactive calculatorOpen calculatorScientific Calculator
Evaluate bounded scientific expressions with functions, constants, powers, factorials, and explicit degree or radian mode—without JavaScript eval.
Interactive calculatorOpen calculatorUnit Converter
Convert length, area, volume, mass, temperature, speed, pressure, and decimal or binary data units with compatible-unit controls.
Interactive calculatorOpen calculatorDate Calculator
Find calendar days and weekdays between ISO dates, choose inclusive counting, or add a signed whole-day interval without daylight-saving drift.
Interactive calculatorOpen calculatorHow this shelf is organized
Deterministic by default
Arithmetic, dates, units, bills, discounts, and loan schedules run in the browser.
Assumptions stay nearby
Every result retains its operation, unit, rate, or model boundary.
External data is dated
When a tool requests reference data, freshness and cached state appear beside the input.
All math & education calculators
41 calculators and planning guides are available. 41 offer interactive results; every page explains its assumptions, scope, and limitations. Use the details on each page to choose the tool that fits your question.
System of Equations Calculator
Solve 2x2 or 3x3 systems of linear equations with Gaussian elimination, solution type, determinant, residual, and clear limits.
Interactive calculatorOpen calculatorRocket Equation Calculator
Calculate ideal rocket delta-v from wet mass, dry mass, and specific impulse. See mass ratio, propellant fraction, exhaust velocity, formula, and limits.
Interactive calculatorOpen calculatorHomeschool GPA Calculator
Calculate credit-weighted homeschool GPA with entered 0–4 grade points and optional honors or advanced-course weight. See quality points and transcript cautions.
Interactive calculatorOpen calculatorBasic Calculator
Calculate arithmetic, percentages, percent change, division, and powers with a clear operation label and keyboard-friendly inputs.
Interactive calculatorOpen calculatorScientific Calculator
Evaluate bounded scientific expressions with functions, constants, powers, factorials, and explicit degree or radian mode—without JavaScript eval.
Interactive calculatorOpen calculatorUnit Converter
Convert length, area, volume, mass, temperature, speed, pressure, and decimal or binary data units with compatible-unit controls.
Interactive calculatorOpen calculatorDate Calculator
Find calendar days and weekdays between ISO dates, choose inclusive counting, or add a signed whole-day interval without daylight-saving drift.
Interactive calculatorOpen calculatorPercentage Change Calculator
Calculate absolute and percentage change, multiplier, percentage-point difference, and recovery after a loss, with zero and negative-value handling.
Interactive calculatorOpen calculatorMean, Median, Mode & Range Calculator
Enter a number list to calculate count, sum, mean, median, modes, range, and optional population and sample standard deviation with sorted values.
Interactive calculatorOpen calculatorCone Volume Calculator
Calculate the volume of a cone or truncated cone (frustum) from radius or diameter and perpendicular height, with slant height and unit conversions.
Interactive calculatorOpen calculatorAge Calculator
Find exact age in years, months and days on any date, plus total months, weeks and days, the next birthday, and the weekday of birth, with a Feb 29 rule.
Interactive calculatorOpen calculatorCircle Calculator
Enter a circle’s radius, diameter, circumference or area to get all four measures with the working, plus arc length and sector area for any angle.
Interactive calculatorOpen calculatorComplex Number Calculator
Add, subtract, multiply and divide complex numbers, or find a conjugate, polar form, integer power or all nth roots, with modulus and argument in degrees or radians.
Interactive calculatorOpen calculatorUTM Coordinate Converter
Convert UTM zone, easting and northing to WGS84 latitude and longitude, or latitude and longitude to UTM, with decimal degrees, DMS and a round-trip check.
Interactive calculatorOpen calculatorDice Probability Calculator
Exact probability that a roll of up to 20 dice with 2 to 100 sides plus a modifier is at least, exactly or at most a target, with mean, spread and percentiles.
Interactive calculatorOpen calculatorElastic Modulus Calculator
Calculate Young’s modulus from tensile test force, cross-section, gauge length and extension, or from stress and strain, in MPa, GPa and psi.
Interactive calculatorOpen calculatorFeeds and Speeds Calculator
Turn a cutting speed and chip load from your tooling data into spindle RPM and feed rate, in inch (SFM, IPM) or metric (m/min, mm/min), with an RPM cap.
Interactive calculatorOpen calculatorFlight Time Calculator
Find the real flight duration between two local departure and arrival times with UTC offsets, or the local arrival time from a departure time and flight length.
Interactive calculatorOpen calculatorFraction Calculator
Add, subtract, multiply or divide fractions and mixed numbers exactly, simplify a fraction, turn a decimal into a fraction, or switch improper and mixed forms.
Interactive calculatorOpen calculatorGrade Curve Calculator
Curve a list of test scores with a square root curve, top-score shift, flat points, target mean or bell-curve z-score mapping, and compare means and spreads.
Interactive calculatorOpen calculatorGrade Calculator
Weight up to five categories into a current course grade, then find the final exam score needed for a target grade, with your own letter-grade scale.
Interactive calculatorOpen calculatorkVA to Amps Calculator
Convert kVA to amps, amps to kVA, or kW to kVA with power factor for single-phase or three-phase line-to-line voltage, with kW and kvar shown.
Interactive calculatorOpen calculatorLong Division Calculator
Divide decimals exactly by long division: quotient to up to 20 places, repeating-decimal notation, integer quotient and remainder, and bring-down steps.
Interactive calculatorOpen calculatorMetal Weight Calculator
Weigh steel, stainless, aluminum, copper or brass plate, bar, pipe, tube or rebar from its dimensions in inches or mm, with total weight and material cost.
Interactive calculatorOpen calculatorNumber to Words Calculator
Write a number in English words using the short scale: decimals as "point five", cheque-style dollars and xx/100, or ordinals such as "twenty-first".
Interactive calculatorOpen calculatorPolynomial Division Calculator
Divide two polynomials entered as expressions or coefficient lists and get the exact quotient and remainder with fractions, long-division steps and the identity.
Interactive calculatorOpen calculatorPulley and Belt Calculator
Calculate driven pulley RPM, speed ratio, open or crossed belt length, wrap angle on the small pulley and belt speed from diameters and center distance.
Interactive calculatorOpen calculatorQuadratic Factoring Calculator
Factor ax² + bx + c and solve it: discriminant, real or complex roots with exact surd form, vertex, axis of symmetry, and the sum and product of the roots.
Interactive calculatorOpen calculatorRatio Calculator
Simplify a ratio, solve A:B = C:x, build an equivalent ratio table, or find y from direct (y = kx) or inverse (y = k/x) variation, with the constant k.
Interactive calculatorOpen calculatorRC Filter Calculator
Find the cutoff frequency, time constant, gain in dB and phase shift of a first-order RC low-pass or high-pass filter, with a response table around cutoff.
Interactive calculatorOpen calculatorReadability Calculator
Paste English text or enter word, sentence and syllable counts to get Flesch Reading Ease, Flesch–Kincaid Grade Level and the averages behind them.
Interactive calculatorOpen calculatorReading Fluency Calculator
Calculate words correct per minute (WCPM) from words attempted, errors and reading time, with accuracy and error rate for an oral reading passage.
Interactive calculatorOpen calculatorResistor Color Code Calculator
Read 4-, 5- and 6-band resistor color codes per IEC 60062: resistance in Ω, kΩ or MΩ, tolerance, minimum to maximum range and temperature coefficient.
Interactive calculatorOpen calculatorSpeech Time Calculator
Paste a speech or enter a word count to estimate speaking time at your own pace, with paragraph pauses, word, character and sentence counts and silent reading time.
Interactive calculatorOpen calculatorSpeed Distance Time Calculator
Solve average speed, distance or travel time, then see the speed in mph, km/h, m/s and knots and the pace per mile and per kilometer.
Interactive calculatorOpen calculatorTime Duration Calculator
Find the time between two clock times (overnight aware), add or subtract hours and minutes from a time, or convert h:mm:ss to decimal hours and minutes.
Interactive calculatorOpen calculatorTimecode Calculator
Add or subtract SMPTE timecodes, or convert between timecode and frame counts at 23.976 to 60 fps, including 29.97 and 59.94 drop-frame, with real-time duration.
Interactive calculatorOpen calculatorTriangle Calculator
Solve a triangle from SSS, SAS, ASA, AAS or SSA (including the two-solution case) or base and height: all sides, angles, area, perimeter and type.
Interactive calculatorOpen calculatorTyping Speed Calculator
Turn typed characters, uncorrected errors and elapsed time into gross words per minute, net WPM, accuracy and characters per minute, with the conventions shown.
Interactive calculatorOpen calculatorMass–Volume & Density Calculator
Solve mass, volume or density with separate units, including US liquid and Imperial gallons. Enter whole-fluid density to bridge mass and volume.
Interactive calculatorOpen calculatorMTG Land Draw Probability Calculator
Calculate land-draw probabilities without replacement, inspect the complete supported distribution, and compare entered land counts for the same library.
Interactive calculatorOpen calculator