By Zencalcy Editorial TeamLast reviewed About us
Round pools hold less water than their footprint suggests because the circular area is only 78.5% of the square that contains it. Enter the diameter and water depth — not the wall height, which is usually several inches taller than the water line.
Gallons in a round or oval above-ground pool.
Gallons = π × (d ÷ 2)² × depth × 7.4805
For an oval, use the geometric mean of the two diameters: d = √(long × short). Water depth is typically 6–8 inches below the top rail on an above-ground pool.
| Symbol | Meaning |
|---|---|
| d | Pool diameter. |
| h | Water depth. |
| V | Volume in gallons. |
π × 12² × 4 = 1,810 cu ft, or 13,540 gallons (51,300 litres).
Continue with the Pool Calculator, Pond Calculator, Tank Volume Calculator, or the Pipe Volume Calculator — or browse more tanks, pools & flow and all construction calculators.
About 13,500 gallons at 4 ft of water, or 15,200 at 4.5 ft.
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.
Estimate decking boards by length, screws, hidden fasteners and waste
Calculate concrete blocks needed for wall construction
Calculate full deck materials list including boards, joists, beams, posts, and cost estimates
Price hardwood the way the lumber yard does — by board footage.
Turn measured dimensions into the cubic yards concrete and gravel are sold in.
How many gallons it takes to cover an area at a given depth.
Content updated: September 2026