Pool Volume Calculator
Find your pool volume in gallons, liters, and cubic meters. Choose the shape, enter the dimensions, and use the average of your shallow and deep-end depths.
Pool volume reference table
These common-size tables are generated from the same formulas as the calculator. Values use a level average depth of 3, 4, or 5 ft unless marked metric.
Rectangular pool (7.48 coefficient)
| Dimensions | Average depth 3 ft | Average depth 4 ft | Average depth 5 ft |
|---|---|---|---|
| 10 × 20 ft | 4,488 gal | 5,984 gal | 7,480 gal |
| 15 × 30 ft | 10,098 gal | 13,464 gal | 16,830 gal |
| 16 × 32 ft | 11,489 gal | 15,319 gal | 19,149 gal |
| 18 × 36 ft | 14,541 gal | 19,388 gal | 24,235 gal |
| 20 × 40 ft | 17,952 gal | 23,936 gal | 29,920 gal |
Round pool (5.875 coefficient)
| Dimensions | Average depth 3 ft | Average depth 4 ft | Average depth 5 ft |
|---|---|---|---|
| 12 ft | 2,538 gal | 3,384 gal | 4,230 gal |
| 15 ft | 3,966 gal | 5,288 gal | 6,609 gal |
| 18 ft | 5,711 gal | 7,614 gal | 9,518 gal |
| 21 ft | 7,773 gal | 10,364 gal | 12,954 gal |
| 24 ft | 10,152 gal | 13,536 gal | 16,920 gal |
| 27 ft | 12,849 gal | 17,132 gal | 21,414 gal |
| 30 ft | 15,863 gal | 21,150 gal | 26,438 gal |
Oval pool (5.875 coefficient)
| Dimensions | Average depth 3 ft | Average depth 4 ft | Average depth 5 ft |
|---|---|---|---|
| 12 × 24 ft | 5,076 gal | 6,768 gal | 8,460 gal |
| 15 × 30 ft | 7,931 gal | 10,575 gal | 13,219 gal |
| 16 × 32 ft | 9,024 gal | 12,032 gal | 15,040 gal |
| 18 × 33 ft | 10,469 gal | 13,959 gal | 17,449 gal |
Metric reference
| Dimensions | Average depth 1.2 m | Average depth 1.5 m |
|---|---|---|
| 6 × 3 m | 21.6 m³ / 21,600 L | 27.0 m³ / 27,000 L |
| 8 × 4 m | 38.4 m³ / 38,400 L | 48.0 m³ / 48,000 L |
| 10 × 5 m | 60.0 m³ / 60,000 L | 75.0 m³ / 75,000 L |
| 12 × 6 m | 86.4 m³ / 86,400 L | 108.0 m³ / 108,000 L |
How to calculate pool volume
Rectangular pool
Multiply length × width × average depth × 7.48. For a 15 × 30 ft pool with a 4 ft average depth: 15 × 30 × 4 × 7.48 = 13,464 gallons.
Round pool
Multiply diameter² × average depth × 5.875. The 5.875 coefficient combines the circle area factor (π ÷ 4) with 7.48 gallons per cubic foot.
Oval pool
Multiply length × width × average depth × 5.875. This treats the outline as an ellipse and is more accurate than using the rectangular coefficient.
Kidney-shaped or irregular pool
Measure the longest outside length and width, multiply the outside rectangle by 0.85, then multiply by average depth × 7.48. This is an estimate with about ±10% accuracy because kidney shapes vary.
Metric pool
Multiply length × width × average depth in meters to get cubic meters. Multiply cubic meters by 1,000 for liters, or divide liters by 3.78541 to get US gallons.
How many gallons is my pool?
A typical US residential pool holds about 10,000–30,000 gallons. A 15 × 30 ft rectangular pool with a 3 ft shallow end and 5 ft deep end has a 4 ft average depth and holds about 13,464 gallons. Measure your own pool rather than relying on a builder's estimate, especially before calculating a chemical dose.
Average depth: the number most people get wrong
If the shallow end is 3 ft and the deep end is 5 ft, average depth is 4 ft — not 3 and not 5:(3 + 5) ÷ 2 = 4. Using only the shallow-end depth can make the volume, and every later chemical dose, wrong by roughly 30%.
If there is a small diving well or deep-water pocket, do not use its full depth for the whole pool. If an 8 ft section covers only a small part of the floor, use the main pool depth and accept a controlled estimate rather than letting that small area distort the whole result.
To verify depth, push a straight pole or marked rod to the pool floor and mark it at the waterline. Measuring the actual water depth is more reliable than guessing from a brochure or memory.
Why your pool volume matters
Volume is the base number behind every pool chemical dose. If the volume is wrong, chlorine, shock, and stabilizer calculations are wrong by the same percentage. Use your result with the Pool Shock Calculator, Pool Chlorine Calculator, and Pool Stabilizer Calculator.
Frequently asked questions
How many gallons is a 15 × 30 pool?
At a 4 ft average depth, a 15 × 30 ft rectangular pool holds about 13,464 gallons. Use the calculator above with your actual shallow and deep-end depths for a closer estimate.
What is the average depth of a pool?
For a pool with a shallow end and deep end, average depth is (shallow depth + deep depth) ÷ 2. A 3 ft shallow end and 5 ft deep end therefore have a 4 ft average depth — do not use only the shallow end.
How do I calculate gallons in a round pool?
Multiply diameter squared by average depth by 5.875. For example, a 24 ft round pool at a 4 ft average depth holds about 13,536 gallons.
How many liters is my pool?
Convert cubic meters to liters by multiplying by 1,000, or convert gallons to liters by multiplying by 3.78541. The calculator shows gallons, liters, and cubic meters together.
How do I convert gallons to liters?
Multiply US gallons by 3.78541. For a quick estimate, 10,000 gallons is about 37,854 liters.
How accurate is a pool volume estimate?
Rectangular and round pool estimates are usually within about ±5% when dimensions and depths are measured carefully. Kidney-shaped and irregular pools use an outside rectangle multiplied by 0.85 and are typically within about ±10%.
How much water does an average pool hold?
Most US residential pools hold roughly 10,000–30,000 gallons, although above-ground, plunge, lap, and very deep pools can fall outside that range.
How do I calculate the volume of a kidney-shaped pool?
Measure the longest outside length and width, multiply that outside rectangle by 0.85, then multiply by average depth and 7.48. This is an estimate with about ±10% accuracy because kidney shapes vary.