Building & decorating / Pools
Pool Volume Calculator (Litres and Gallons)
Work out how much water a rectangular, round, or oval swimming pool holds from its size and its shallow and deep end depths, in litres, cubic metres, and US and UK gallons, for filling, heating, and dosing chemicals.
Pool Volume Calculator (Litres and Gallons): Volume is the surface area times the average depth. A 10 × 5 m pool sloping from 1 m to 2 m averages 1.5 m deep and holds 75 m³, 75,000 litres, or about 19,800 US gallons. Round pools use π × radius², and oval ones π × half the length × half the width. Runs 100% locally in your browser with zero server file uploads.
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- Home & family tools
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Volume is the surface area times the average depth: for a pool sloping evenly from a shallow to a deep end, that is the depth halfway between them. Oval pools use π × half the length × half the width. Chemical doses on product labels are per 10,000 litres or gallons, so use these volumes to scale them, and fill to the normal water line, not the top edge.
Example in feet
A 32 × 16 ft pool from 3.5 to 8 ft deep holds 2,944 cubic feet, about 22,000 US gallons.
Smaller tanks
For fish tanks, use the aquarium volume calculator.
How to use it
- Choose the shape and metres or feet.
- Enter the length and width, or the diameter, and both end depths.
- Read the volume in litres and gallons.
Privacy & limitations
Everything is calculated in your browser.
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Frequently asked questions
Why does the volume matter?
Chlorine, pH, and other treatments are dosed per volume, and heaters, pumps, and filling costs all depend on it.
What if my pool has a steep drop rather than a slope?
Split it into two parts, the shallow and the deep area, work out each as a flat pool, and add them together.
How long will it take to fill?
Divide the volume by your hose's flow, often 15 to 30 litres a minute: 75,000 litres at 20 L/min takes about 62 hours.
Free tool · runs in your browser · no account required