Pool Volume Calculator
Find how many gallons of water your pool holds, for rectangle, round and oval pools, with fill time.
Results
| Item | Value |
|---|
Quick Answer
Pool gallons = length × width × average depth × 7.48. A 32 ft by 16 ft pool that goes from 3.5 ft to 6 ft deep has an average depth of 4.75 ft, so it holds about 18,193 gallons. For a round pool, use π × radius² × depth × 7.48.
Embed this calculator
Adjust the size if needed, then copy the code below into your page or blog. The calculator will load in an iframe and stay updated automatically.
Table of Contents
- Pool Volume Calculator
- Quick Answer
- Related Calculators
- How This Pool Volume Calculator Works
- How to Use the Pool Volume Calculator
- Core Formulas
- Key Terms
- Worked Example
- Real-Life Examples
- Gallons vs Liters vs Cubic Feet
- Gallons in Common Pool Sizes
- Why Pool Volume Matters
- Common Mistakes to Avoid
- Frequently Asked Questions
- References & Sources
How This Pool Volume Calculator Works
Pick the shape of your pool and enter its size in feet. The calculator finds the surface area, multiplies by the average depth to get cubic feet, and converts that to US gallons and liters. Add your hose flow rate to see roughly how long it takes to fill.
Quick explanation: gallons = surface area × average depth × 7.48.
- Average depth: (shallow end + deep end) ÷ 2.
- Round pools: use the diameter across the middle.
- Oval pools: use the longest length and widest width.
How to Use the Pool Volume Calculator
- Choose the shape of your pool.
- Enter the length and width, or the diameter for a round pool, in feet.
- Enter the water depth at the shallow end and at the deep end.
- Optionally, enter your hose flow rate in gallons per minute.
- Press Calculate to see gallons, liters, cubic feet and fill time.
Core Formulas
- Rectangle: length × width × average depth
- Round: π × (diameter ÷ 2)² × average depth
- Oval: π × (length ÷ 2) × (width ÷ 2) × average depth
- Gallons: cubic feet × 7.48052
- Fill time: gallons ÷ flow rate in gallons per minute
Key Terms
- Average depth: the mean of the shallow and deep end depths.
- Turnover: the time a pump takes to move the full pool volume through the filter.
- Gallons per minute (gpm): the flow rate of a hose or pump.
- Cubic foot: a cube 1 ft on each side, holding about 7.48 US gallons.
Worked Example
An above-ground round pool is 24 ft across and 4 ft deep.
- Area = π × 12² = 452.4 sq ft
- Volume = 452.4 × 4 = 1,809.6 cu ft
- Gallons = 1,809.6 × 7.48 ≈ 13,536 gallons
Real-Life Examples
- Dosing chlorine: knowing your pool holds about 18,193 gallons lets you follow product labels that dose per 10,000 gallons.
- Above-ground pool: an oval 30 ft by 15 ft, from 4 to 5 ft deep, holds about 11,897 gallons.
- Filling from a hose: at 10 gallons per minute, the 24 ft round pool takes about 23 hours to fill.
- Small kiddie pool: 8 ft round and 1.5 ft deep holds about 564 gallons.
Gallons vs Liters vs Cubic Feet
- US gallons: used for pool chemicals and pumps in the US. 1 cubic foot = 7.48 gallons.
- Liters: used in most other countries. 1 gallon = 3.785 liters.
- Cubic feet: the raw volume from your measurements.
- Cubic meters: 1 m³ = 1,000 liters, about 264 gallons.
Gallons in Common Pool Sizes
| Pool | Average depth | Gallons |
|---|---|---|
| 12 ft round | 3 ft | 2,538 |
| 18 ft round | 4 ft | 7,614 |
| 24 ft round | 4.5 ft | 15,228 |
| 15 × 30 ft oval | 4 ft | 10,575 |
| 12 × 24 ft rectangle | 4.25 ft | 9,156 |
| 16 × 32 ft rectangle | 4.75 ft | 18,193 |
| 20 × 40 ft rectangle | 5.75 ft | 34,410 |
Why Pool Volume Matters
- Chemicals: chlorine and other treatments are dosed per gallon.
- Pump and filter size: they should turn over the full volume in a set time.
- Heating: heater size and running cost depend on volume.
- Filling: water delivery and utility costs depend on gallons.
Common Mistakes to Avoid
- Measuring to the top of the wall. Measure to the actual water level.
- Using the deep end only. Use the average of shallow and deep.
- Using radius as diameter. For round pools, enter the full width across.
- Ignoring steps and benches. They reduce volume slightly in large pools.
- Mixing US and UK gallons. This calculator uses US gallons.
Frequently Asked Questions
Multiply length, width and average depth in feet, then multiply by 7.48.
At 4 ft deep, about 13,536 gallons.
About 7.48 US gallons.
Add the shallow and deep end depths and divide by 2.
Divide the gallons by your hose flow in gallons per minute. Many garden hoses deliver roughly 5 to 10 gpm.
Split it into simple shapes, find each volume, and add them together.
It varies with sun, wind, heat and humidity. A pool cover can cut evaporation a lot, saving water and heating costs.
Use the average depth. For a pool with a flat shallow area and a long slope, split it into sections and add each one.
Not always. Sellers often give the frame size. Measure the inside at the water line for an accurate result.
Time how long it takes to fill a 5-gallon bucket, then divide 5 by the minutes.
References & Sources
| Source | Used For | Link |
|---|---|---|
| NIST, Unit conversion | Cubic feet to gallons. | https://www.nist.gov/pml/owm/metric-si/unit-conversion |
| CDC, Healthy Swimming | Pool water care and safety. | https://www.cdc.gov/healthy-swimming/ |