Quick answer
Use pool shape, measured dimensions, and average depth to estimate gallons before sizing filters, planning water changes, or using any chemical-dosing label. Measure carefully and treat the result as a planning volume, not a lab reading.
Best for: comparing realistic scenarios before acting. Not for: final professional guidance, emergency decisions, or replacing product labels and local requirements.
How to use the calculator
- Enter the measurements, quantities, costs, or target values requested above.
- Adjust optional assumptions such as waste, overhead, product strength, retention days, or multipliers.
- Read both the main result cards and any warning notes. The warnings are part of the answer, not fine print.
- Use the share, copy, or print/PDF controls when you want to save the scenario.
What the results mean
The primary result is the main number to use first. Supporting cards show the inputs, ranges, assumptions, or follow-up checks that explain how to interpret it.
Decision notes for this calculator
Use: Planning aid
Length/width or diameter and average depth dominate gallons; a small depth error can change chemical doses materially.
What to do next
Use this volume estimate before any pool-chemical page, and remeasure unusual shapes in smaller sections.
Save this scenario
Use Share to copy a clean URL with your inputs, Copy result for notes or email, and Print / PDF for a saved scenario. If the result looks wrong, report an issue with the Pool Volume Calculator.
Formula / methodology
Rectangle gallons = length × width × average depth × 7.48052. Round pools use π × radius² × average depth × 7.48052. Oval pools use π × (length ÷ 2) × (width ÷ 2) × average depth × 7.48052. Average depth = (shallow depth + deep depth) ÷ 2.
Assumptions and limitations
- Inputs are assumed to be measured accurately and entered in the units shown.
- Rounding is intentional so the result is easier to use in real decisions.
- Vendor-specific behavior, local code, product labels, and regional pricing can override a generic calculator.
- Health, legal, tax, emergency, structural, chemical, and other high-risk decisions need qualified guidance beyond a web calculator.
Example calculation
Input: rectangular 30 ft × 15 ft pool with 3 ft shallow and 6 ft deep ends. Average depth is 4.5 ft, volume is 30 × 15 × 4.5 × 7.48052 = about 15,148 gallons.
Common mistakes
- Using chemical dose text instead of a volume formula.
- Using deep-end depth instead of average depth.
- Forgetting that round and oval pools use curved area formulas.
- Dosing chemicals before verifying the actual water volume.
FAQ
What formula does this page use?
Rectangular pools use length × width × average depth × 7.48052. Round pools use π × radius² × average depth × 7.48052. Oval pools use π × half length × half width × average depth × 7.48052.
What changes the result the most?
Measured length/width/diameter and average depth drive the result most. A small depth error can materially change gallons, especially on large pools.
Is this a final professional answer?
No. Treat it as a planning volume estimate. Verify unusual shapes, sloped bottoms, tanning ledges, spas, steps, and chemical dosing against product labels or a qualified pool professional.
Why does this page show warnings?
Warnings call out measurements or assumptions that can materially change the gallon estimate or make downstream chemical dosing unsafe.
Can I share this scenario?
Yes. The share button copies a URL with the current inputs, while the main page remains the base calculator URL.
Sources and assumptions
References used for this calculator:
Formula basis: geometric volume converted from cubic feet to gallons using 7.48052 gallons per cubic foot. This page intentionally does not recommend chemical amounts; use the volume result as an input to product-label or supported by product labels dosing guidance. Limitation: irregular shapes, attached spas, steps, benches, coves, and inaccurate depth measurements can change real water volume.
Method details
Updated: June 24, 2026. Calculation method: POOL_VOLUME-1.0. Availability: planning aid while the page is improved, sourced, or differentiated.