Pool Volume Calculator
Every pool chemical label, pump spec and heating estimate starts from one number owners routinely get wrong: how much water is actually in the pool. Volume is length × width × average depth for a rectangle, π × radius² × depth for a circle - and 'average depth' is where the honest math happens, because (shallow + deep) ÷ 2 is not what most people eyeball. This calculator runs the geometry for rectangular, oval and round pools in metric or feet.
The outputs come back three ways - liters, US gallons and tonnes of water - because chemical dosing, filtration specs and water bills each speak a different dialect. The note adds the two practical truths: fill level sits near 90% of the coping, and at several thousand liters, evaporation alone is why a pool cover is the highest-ROI accessory you can buy.
How to use
- Pick the pool shape: rectangular, circular or oval.
- Enter dimensions and the average depth - (shallow + deep) ÷ 2.
- Read liters, gallons and tonnes; dose chemicals to the volume, not to guesswork.
Frequently asked questions
How do I calculate my pool's volume?
Rectangle: length × width × average depth. Circle: π × (diameter ÷ 2)² × depth. Oval: π × (length ÷ 2) × (width ÷ 2) × depth. Keep every measurement in the same unit; the calculator converts to liters or US gallons and shows both plus cubic meters for filter-flow specs.
Why is average depth so important?
Because chemicals, heating and pump runtime all scale with true volume, and a wrong average compounds every dose: a pool that's really 60 m³ but treated as 45 gets 25% under-dosed sanitizer - which is how green water happens to tidy people. Measure both ends and split the difference; freeform pools need a honest middle estimate.
How many liters is a typical backyard pool?
A 8×4 m family pool averaging 1.4 m deep holds about 45,000 liters (12,000 US gallons); a small round above-ground (4.5 m, 1.2 m) around 19,000 liters. knowing your number turns chemical labels from riddles into arithmetic - '100 ml per 10,000 L' finally means something.
Does the shape of the floor (hopper, slope) change the math?
Averaging handles simple slopes; deep hopper ends in diving pools add volume the flat average misses - if yours has one, estimate the hopper separately and add it. Freeform kidney shapes: measure width at three points and average. The calculator's ±10% honest range beats most owners' ±30% guesses.