Pool Volume Calculator

Why Pool Volume Matters

Knowing the exact volume of your swimming pool is essential for proper water chemistry, equipment sizing, and maintenance. Chemical dosages for chlorine, pH adjusters, algaecides, and salt are all calculated based on pool volume in litres. Using the wrong volume leads to under-dosing (ineffective treatment) or over-dosing (wasted chemicals and potential health risks).

Our pool volume calculator supports rectangular, circular, oval, and kidney-shaped pools. Enter your pool’s dimensions — length, width, and average depth — and the calculator returns the total volume in litres and gallons.

How to Measure Your Pool

For rectangular pools, measure the length, width, shallow-end depth, and deep-end depth. The average depth is calculated as (shallow + deep) ÷ 2. For round pools, measure the diameter and average depth. Kidney-shaped and freeform pools are trickier — measure the widest and narrowest widths, the overall length, and average depth for an approximate calculation.

Most Australian residential pools hold between 20,000 and 60,000 litres. A standard backyard pool measuring 8m × 4m with an average depth of 1.4m holds approximately 44,800 litres. Plunge pools and spa pools are typically 5,000–15,000 litres, while large lap pools can exceed 80,000 litres.

Using Volume for Chemical Dosing

Once you know your pool volume, you can accurately dose chemicals according to manufacturer instructions. For example, liquid chlorine is typically added at a rate of 1 litre per 10,000 litres of pool water to raise free chlorine by approximately 1 ppm. Salt chlorinators require the correct salt level (usually 3,000–6,000 ppm depending on the unit), which can only be achieved if you know the exact water volume.

Pool volume is also critical when sizing pumps, filters, and heaters. A pump should be capable of turning over the entire pool volume at least once every 6–8 hours. Heaters are rated in kilowatts and their efficiency depends on matching the unit’s output to the volume of water being heated. Our calculator gives you the numbers you need to make informed decisions about your pool equipment.