OTHER · POOL VOLUME
Pool Volume Calculator
Calculate swimming pool water volume in gallons and cubic feet for rectangular, oval, and round pools. Includes fill time estimate based on your hose flow rate.
About This Calculator
Enter your pool shape, dimensions, and average depth to instantly see the total water volume in gallons and cubic feet — plus an estimate of how long it will take to fill at a given hose flow rate. Supports rectangular, oval, and round pools.
How It Works
Rectangular: volume = length × width × avgDepth × 7.48 gal/ft³. Oval: volume = length × width × avgDepth × π/4 × 7.48 gal/ft³. Round: volume = π × (diameter/2)² × avgDepth × 7.48 gal/ft³. Fill time (hrs) = volume (gal) ÷ hose rate (gpm) ÷ 60. Conversion factor: 1 cu ft = 7.48052 US gallons (NIST).
The Formula
gal = L × W × D × 7.48 [rectangular] gal = L × W × D × 0.785 × 7.48 [oval]
- L
- pool length in feet (or diameter for round)
- W
- pool width in feet
- D
- average water depth in feet
- 7.48
- US gallons per cubic foot (NIST)
Frequently Asked Questions
- How do I find the average depth of my pool?
- For pools with a shallow end and a deep end, add the two depths and divide by 2. For example, a pool with a 3-ft shallow end and a 6-ft deep end has an average depth of (3+6) ÷ 2 = 4.5 ft. Most standard in-ground pools use this sloped-bottom design.
- How long will it take to fill my pool with a garden hose?
- A typical garden hose delivers about 9 gallons per minute (gpm). A 12×24 ft pool at 4.5 ft average depth holds about 9,700 gallons — roughly 18 hours of continuous fill time. A filling service or fire hydrant connection can achieve 150–300 gpm, cutting fill time to under 30 minutes.
- Why does the oval pool formula use 0.785?
- An oval (ellipse) with length L and width W has an area of π/4 × L × W ≈ 0.785 × L × W. This accounts for the rounded ends — an oval pool holds about 21.5% less water than a rectangular pool of the same length and width.
- What formula is used for round (circular) pools?
- Area = π × radius² = π × (diameter/2)². Volume = area × average depth. Then convert cubic feet to gallons: × 7.48052.
Estimates only. Coverage figures (sq ft/gallon, bag yield, BTU/sq ft) are industry rules of thumb with real-world variance. Verify quantities with your supplier before purchasing.