Pool Volume Calculator (Litres)
How to calculate pool volume in litres
If you want the right chlorine dose, pump run time, or heating estimate, you need one number first: total water volume. This calculator gives you that value in litres, which is the most practical unit for pool chemicals in many regions.
The tool supports three common pool shapes: rectangular, circular, and oval. You can enter dimensions in metres or feet, and it converts everything behind the scenes before giving your final answer in litres.
Why litres matter for pool maintenance
- Chemical dosing: Most treatment instructions are based on litres of water.
- Filtration planning: Flow rate and turnover targets depend on pool volume.
- Heating cost estimates: Energy required is directly related to water quantity.
- Refill and water bills: Useful when topping up after evaporation or backwashing.
Formulas used by this pool volume calculator
1) Rectangular or square pool
Surface area = length × width
Volume = surface area × average depth
Litres = volume (m³) × 1000
2) Circular pool
Surface area = π × (diameter ÷ 2)²
Volume = surface area × average depth
Litres = volume (m³) × 1000
3) Oval pool
Surface area = π × (length ÷ 2) × (width ÷ 2)
Volume = surface area × average depth
Litres = volume (m³) × 1000
Measuring tips for more accurate results
- Measure internal water dimensions, not outside wall dimensions.
- For sloped pools, use shallow and deep depths to get a better average.
- Take measurements in multiple spots and use the average for irregular pools.
- Do not include steps, benches, or ledges if they significantly reduce water volume.
Quick unit reference
This calculator converts feet to metres automatically when needed. Useful conversion values:
- 1 metre = 3.28084 feet
- 1 cubic metre = 1000 litres
- 1 litre = 0.264172 US gallons
- 1 litre = 0.219969 UK gallons
Frequently asked questions
How accurate is this calculator?
It is very accurate for standard geometric pool shapes when measurements are correct. For freeform pools, divide the pool into sections and calculate each section separately for a better estimate.
What if my pool has a varying floor profile?
Use shallow and deep depths for a quick estimate. If your floor has multiple depth zones, measure each zone and add the volumes together for improved precision.
Do I need exact volume for chemicals?
Exact is ideal, but close estimates still work well. Start with the calculated dose, test the water, and then adjust gradually.
Bottom line
A reliable pool volume in litres helps you avoid over-treating or under-treating your water. Use the calculator above, save your result, and you’ll make better maintenance decisions all season long.