By Zencalcy Editorial TeamLast reviewed About us
Pool chemistry, pump sizing and heating all depend on volume, and pool volume is just length × width × average depth. Most pools have a shallow and a deep end, so use the average of the two rather than the maximum depth — using the deep end alone easily overstates the volume by a third.
Gallons in a rectangular pool, and the fill cost.
Average depth = (shallow + deep) ÷ 2 Gallons = L × W × depth × 7.4805
One cubic foot holds 7.4805 US gallons. A pool with a hopper or a sloping floor is approximated by the average depth; for a complex shape, split it into rectangles and add the volumes.
| Symbol | Meaning |
|---|---|
| L, W | Pool length and width. |
| d | Average water depth. |
| V | Volume in gallons. |
Average depth 4.5 ft gives 2,025 cu ft, or 15,148 gallons — about 57,340 litres.
Continue with the Round Pool Volume Calculator, Pond Calculator, Tank Volume Calculator, or the Pipe Volume Calculator — or browse more tanks, pools & flow and all construction calculators.
About 15,000 gallons at an average depth of 4.5 ft. Each foot of average depth adds roughly 3,370 gallons.
Results use standard construction estimating arithmetic: volumes from measured area and depth, unit weights from published material densities, and code-referenced spans or clearances where the page names a code. Quantities are rounded up to whole saleable units and include the stated waste allowance. These tools are planning aids, not structural design, and do not replace a licensed engineer, a local code check, or a contractor's site measurement.
Reference material used to build and check this calculator:
Last reviewed: September 2026. See how we build and check every tool on the about page.
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Content updated: September 2026