Pools & water systems / Volume
Estimate pool volume
Use the pool shape and average depth to work out an approximate water volume.
Water volume
How much water?
Enter average depth metres.
How it works
Put in your numbers
Use your own rates, times and measurements.
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What it covers: Estimate water volume for rectangular, round, oval and kidney pools.
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How to work out your pool volume
Knowing your pool volume is the first step for dosing chemicals and checking pump turnover. You multiply the water surface area by the average depth. This calculator does that for rectangular, round, oval and kidney shaped pools, or from a surface area you have measured.
- Choose the shape that best fits your pool: rectangular, round, oval or kidney. If you already know the water surface area, choose measured area instead.
- Measure the length and width, or the diameter for a round pool, at the water line. For a kidney pool, measure the width at both the wide and narrow ends. You can work in metres or feet.
- Measure the depth at the shallow end and the deep end. If the floor slopes evenly between them, the average depth is the two added together and divided by two. The calculator can work this out for you.
- The calculator multiplies the water surface area by the average depth to give the estimated volume.
- As a check, 1 cubic metre holds 1,000 litres, and 1 cubic foot holds about 7.48 US gallons.
Tips and common mistakes
- Measure the water, not the top edge of the pool. Measuring to the coping will overestimate the volume.
- An irregular floor, a sudden drop to the deep end, or wide steps and benches can change the real volume. Treat the result as an estimate.
- Kidney and freeform pools are hard to measure exactly. The calculator uses the usual trade estimate for kidney shapes, so treat the figure as a guide.
- Record the volume in your notes for each pool so you do not need to measure it again.
Questions
How do I work out my pool volume?
Multiply the water surface area by the average depth. For a rectangle, that is length times width times average depth. As an illustration only, a pool 8 m long, 4 m wide and 1.5 m deep on average holds 48 cubic metres, which is 48,000 litres.
How many litres are in my pool?
Work out the volume in cubic metres and multiply by 1,000 to get litres. If you measured in feet, work out cubic feet and multiply by about 7.48 to get US gallons. The calculator does the sum once you enter your measurements.
How do I calculate the volume of a round pool?
Measure the diameter across the middle and halve it to get the radius. Multiply the radius by itself, then by 3.14, then by the average depth. That gives the volume in cubic metres or cubic feet, depending on what you measured in.
How do I find the average depth of a pool?
Add the shallow end depth and the deep end depth, then divide by two. This works for a pool with an even slope between the two ends. If the pool has a sudden drop or a deep section, the real volume may be different.
Why do I need to know my pool volume?
Chemical doses on product labels are based on an amount of water, so you need the volume to dose correctly. It also tells you how long your pump takes to turn over the water. A wrong volume is a common cause of over or under dosing.
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