Pool Volume Calculator
Water volume for rectangular, round, oval and kidney pools, with fill time and cost.
Try before you buy.
- Free preview: the rules, dates and checks that apply to your figures, with every computed amount hidden.
- Locked until you unlock it: download and copy.
- Unlock: Pro pass, ₹179 for 30 days or ₹79 for 1 week, a one-time payment that never renews. Unlock: Pro pass, $5.99 for 30 days or $2.99 for 1 week, a one-time payment that never renews.
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Results are estimates from the formulas shown, not a professional design or certification. Have a qualified engineer verify anything safety-critical (structures, electrical installations, gas or pressure systems).
About the Pool Volume Calculator
Work out how much water a pool holds: rectangular, round, oval or kidney-shaped, with a constant depth, a floor sloping from shallow to deep, or a hopper (a deep end that narrows to a smaller bottom). The result is in cubic metres, litres, US gallons and UK gallons, with the time to fill the pool at your hose’s or pump’s flow and the cost at your price of water. Kidney and other free-form pools use the plan area you measure, because their outline cannot be worked out from a length and a width.
The free preview shows the result rows with the values hidden; a Pro pass shows every value, with copy and text or JSON downloads.
How to use it
- Choose the pool’s shape and its depth: constant, a sloped floor or a hopper.
- Enter the dimensions at the water line in your unit, the depths and, for a hopper, the size of its bottom; for a kidney pool, enter its measured plan area in m².
- Enter the fill flow in litres per minute and your price of water per cubic metre.
- Select Calculate; with a Pro pass, copy the working or download it as text or JSON.
Formulas
Plan area: a rectangle is L × W, a round pool πd² ÷ 4, an oval πLW ÷ 4, and a kidney pool the area you measured. Volume = plan area × mean depth. A sloped floor’s mean depth is (shallow + deep) ÷ 2. A hopper adds a frustum below the shallow depth: h(A₁ + A₂ + √(A₁A₂)) ÷ 3, where h is the extra depth and A₁ and A₂ are the top and bottom areas. A US gallon is 3.785411784 L and a UK gallon 4.54609 L (NIST SP 811, appendix B.9).
Limitations
- A kidney or free-form pool needs its measured plan area. A hopper assumes its bottom has the same shape as the top, and a sloped floor that it falls evenly.
- Use the dimensions at the water line. Steps and benches are not counted, and no filtration, dosing or safety design is given.
Privacy
On this device: nothing is sent
Everything is calculated on your device; nothing is uploaded or stored.
Frequently asked questions
What do I get without a pass?
Without a pass, Pool Volume Calculator shows the rules, dates and checks that apply to your figures, with every computed amount hidden. Until you unlock it, the result can’t be downloaded or copied. A Pro, Premium or Ultimate pass, a one-time payment that never renews, unlocks the full result. The pricing page lists the passes and their prices.
How do I measure a kidney-shaped pool?
Measure its plan area: for example, divide the outline into rectangles and part-circles and add up their areas, or take the area from the pool’s drawing. Enter it in square metres; the depths work as for the other shapes.
How long will the pool take to fill?
The fill time is the volume in litres divided by the flow in litres per minute. To find your flow, time how long your hose takes to fill a bucket of known size.