Pool Gallons Calculator
Buy Pool Gallons at Home Depot →How this calculator works
Pool volume is length times width times average depth, giving cubic feet — then multiplied by 7.48, the number of gallons in a cubic foot, to get total gallons.
Formula: Gallons = Length (ft) × Width (ft) × Average depth (ft) × 7.48.
Worked example
A 20 ft × 10 ft pool with a 60-inch (5 ft) average depth:
- Average depth in feet: 60 ÷ 12 = 5 ft
- Gallons: 20 × 10 × 5 × 7.48 = 7,480 gallons
- At $0.01/gallon for fill water, that’s $74.80.
Coverage reference
| Pool size | Average depth | Gallons |
|---|---|---|
| 15 ft × 10 ft | 5 ft | 5,610 gallons |
| 20 ft × 10 ft | 5 ft | 7,480 gallons |
| 24 ft × 12 ft | 5 ft | 10,771 gallons |
How to measure your pool
For a rectangular pool, measure the interior length and width. For an irregular or freeform pool, this calculator gives a rough estimate treating it as a rectangle — a pool professional can give you an exact volume from your pool’s actual shape.
Frequently asked questions
How do I calculate my pool's volume in gallons?
Multiply length x width x average depth (in feet), then multiply by 7.48 gallons per cubic foot. This calculator does that automatically — enter your pool's dimensions and average depth in inches, and it converts everything for you.
What is 'average depth' for a pool with a shallow and deep end?
Add the shallow-end depth and deep-end depth together and divide by 2. For example, a pool that's 3 ft at the shallow end and 8 ft at the deep end has an average depth of 5.5 ft (66 inches).
Why is depth entered in inches here instead of feet?
For consistency with every other calculator on this site, which all use inches for depth inputs. A typical residential pool averages 48-72 inches (4-6 ft) deep — enter your value in inches and the calculator converts it internally.
What is the 'cost' figure showing for a pool calculator?
It estimates the cost to fill your pool with water, using a default of $0.01 per gallon (adjust the price field to your local water rate). It does not include chemicals, heating, or filtration costs.
Estimates only. Verify quantities with your supplier before purchasing.