Rectangular Pool Volume Calculator
Estimate how many gallons a rectangular pool holds from its length, width and average depth.
Calculator
| Liters | 63,702 L |
|---|---|
| Cubic feet | 2,250 ft³ |
| Hours to fill with a hose at 10 gal/min | 28 hours |
How it is calculated
30 × 15 × 5 ft = 2,250 cubic feet × 7.48 gallons per cubic foot = 16,830 gallons.
About this calculator
Pool volume in gallons is length × width × average depth (all in feet) × 7.48, the number of US gallons in a cubic foot. For a sloped floor, average depth is the shallow end plus the deep end, divided by two.
Knowing the volume helps with chemical dosing and with estimating fill time. Pools are usually filled a few inches below the rim, so real water volume is slightly less than the full-depth figure.
Worked examples
| Project | US gallons | Rough cost |
|---|---|---|
| a 16x32 ft rectangular pool with a 5 ft average depth | 19,149 gal | $76.60 – $230 |
| a 20x40 ft rectangular pool with a 5 ft average depth | 29,920 gal | $120 – $359 |
| a 12x24 ft rectangular pool with a 4 ft average depth | 8,617 gal | $34.47 – $103 |
| a 20x50 ft rectangular pool with a 6 ft average depth | 44,880 gal | $180 – $539 |
Buying notes
- The fill time shown assumes about 10 gallons per minute from a hose. Real flow varies with pressure and hose size.
- Measure inside the pool, not the outside of the walls or coping.
Quick answers by size
Click a size for the exact quantity and cost.
How to measure and use this calculator
- Measure the pool's length and width.
- Measure the average water depth: shallow plus deep end, divided by two.
- Read gallons and fill time.
- Use the volume to dose chemicals.
Common mistakes
- Using the full depth instead of average depth.
- Measuring the outside of the pool wall.
- Assuming a pool is full to the rim.
Tips
- Average depth = (shallow end + deep end) ÷ 2 for a sloped floor.
- Pools are rarely filled to the very top; water level is a few inches below the rim.
- Knowing the volume helps with chemical dosing.
Frequently asked questions
How many gallons is a 16x32 pool?
About 19,000 gallons at a 5 ft average depth.
How do I find the average depth of my pool?
Add the shallow-end and deep-end depths and divide by two. For pools with a more complex floor, take several depth readings and average them.
How long does it take to fill a pool?
Divide the gallons by your flow rate in gallons per minute to get minutes, then divide by 60 for hours.