Find out how many gallons (or liters) your swimming pool holds — for any shape, with or without a sloped bottom. Free, instant, no email required.
Pool shape
Depth
Drag the orange handles to set where the slope starts and ends — or type the Shallow and Deep lengths above.
Measure the depth of your water, not the height of the wall. For pools with a slope, use Shallow + Deep so we average correctly.
Estimated volume
17,235gallons
≈ 65,242 liters
Servicing more than one pool? You don’t have to save — “Use in Chlorine Calculator” carries this volume over without storing anything.
L × W × Depth × 7.48 → 32 × 16 × [(9.6·3.5 + 12.8·((3.5+5.5)÷2) + 9.6·5.5) ÷ 32.0] = 4.5 ft avg
7.48 = U.S. gallons in 1 cubic foot of water.
Four quick tips for getting the right numbers into the fields above.
Use a marked pole or weighted tape from the waterline straight down to the floor.
Enter both depths in the Depth section and we average them — or use Sloped sections for a section-accurate result.
Measure the widest points across the long axis and the short axis — that's what goes into Length and Width.
Mentally break it into rectangles and circles. Use Freeform mode and add each section separately — we sum them.
Approximate gallons for standard residential pool dimensions.
| Shape | Dimensions | Gallons |
|---|---|---|
| Rectangle | 10 × 20 × 5 ft | 7,480 |
| Rectangle | 12 × 24 × 5 ft | 10,771 |
| Rectangle | 14 × 28 × 5 ft | 14,661 |
| Rectangle | 16 × 32 × 5 ft | 19,149 |
| Rectangle | 16 × 32 × 6 ft | 22,979 |
| Rectangle | 20 × 40 × 5 ft | 29,922 |
| Round | 15 ft Ø × 4 ft | 5,288 |
| Round | 18 ft Ø × 4 ft | 7,615 |
| Round | 24 ft Ø × 4 ft | 13,540 |
| Round | 27 ft Ø × 4 ft | 17,137 |
| Oval | 15 × 30 × 4 ft | 10,579 |
| Oval | 18 × 33 × 4 ft | 13,961 |
Quick answers to the questions homeowners ask about pool volume.
A 16-by-32-foot rectangular pool holds roughly 19,150 gallons at an average depth of 5 feet, or about 23,000 gallons at 6 feet of average depth. Depth makes the biggest difference: every extra foot of average depth adds about 16 × 32 × 7.48 = 3,830 gallons.
If your pool has a sloped bottom, add the shallow-end depth and the deep-end depth, then divide by two. That gives you the average for a uniform slope. For pools with a flat shallow section, a sloped middle, and a flat deep end, the sloped-sections mode in this calculator handles the geometry more precisely — measure each section length and the two depths.
Most in-ground residential pools in the US hold between 15,000 and 30,000 gallons. A common 16 × 32 with a 3-foot to 8-foot slope lands around 21,000 gallons. Above-ground pools are smaller: a 24-foot round above-ground pool at 4 feet deep is about 13,500 gallons.
Spas and hot tubs are much smaller — most residential spas hold 300 to 1,000 gallons. The math is the same (cylinder or rectangular box), but spas often have a seat or step bench that takes up water space. Use the 'Spa has a seat / step bench' option in this calculator to subtract that bench from the footwell volume automatically.
Multiply gallons by 3.785 to get liters. So a 20,000-gallon pool is about 75,700 liters. This calculator displays both — just toggle "Gallons" or "Liters" at the top.
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