Pool Volume Calculator
How many gallons the pool holds — for chemicals and liner talk, not a construction bid. Click any i for detail.
Pool dimensions
Shape
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Shape
Rectangle uses L×W. Oval uses an ellipse. Circle uses diameter. |
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Length (ft)
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Length
Long axis in feet. |
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Width (ft)
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Width
Short axis in feet. |
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Diameter (ft)
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Diameter
Round pools only. |
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Average depth (ft)
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Depth
(Shallow + deep) ÷ 2. A 3–8 ft pool averages 5.5 ft if the break is mid-pool. |
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Freeboard trim (%)
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Freeboard
Leave 0 if you fill to the tile line. Trim a few percent if you never fill to the coping. |
How to use this calculator
- Pick rectangle, oval, or circle.
- Enter the dimensions that appear for that shape.
- Use average depth, not the deep-end number alone.
- Optional freeboard trims gallons if you underfill.
Results explained
Gallons ≈ cubic feet × 7.48052. Rectangle volume is L×W×depth. Circle is πr²×depth. Oval is π×(L/2)×(W/2)×depth.
Quick reference: pool gallons
1 cubic foot holds about 7.48 gallons.
| Item | Detail |
|---|---|
| 32×16×5 ft rectangle | ≈ 19,150 gal |
| 18 ft round × 4 ft | ≈ 7,610 gal |
| Salt / chlorine dose | Uses gallons — this page stops at volume |
| Liner replacement | Uses surface area, not gallons |
For liner dollars see the pool liner replacement cost calculator.
How the estimate is built
cu ft from the selected shape; gallons = cu ft × 7.48052 × (1 − freeboard%).
Example scenario
A 32×16 ft rectangle, 5 ft average depth → 2,560 ft³ ≈ 19,150 gallons.
FAQ
Kidney / freeform?
Split into rectangles and ovals, or use a manufacturer gallon plate.
Above-ground?
Use circle or oval and the wall height as average depth if the floor is flat.
Hot tub?
Same math; typical spas are 300–500 gallons, not 20,000.