Calculate Pool Volume in Litres
Use this swimming pool volume calculator to estimate litres, cubic metres, and gallons for common pool shapes.
Why a pool litre calculator matters
Knowing your pool volume in litres is one of the most useful numbers for pool maintenance. Whether you are balancing chlorine, adjusting pH, adding salt, or running a filtration schedule, nearly every treatment recommendation depends on water volume. If your litre estimate is off, chemical dosing can be too weak or too strong.
This calculator is designed to help homeowners quickly estimate volume for common residential pool shapes. It is especially useful when you want a fast swimming pool volume calculator before adding chemicals or planning water replacement.
How this calculator works
1) Choose a shape
Select rectangular, circular, or oval. The calculator uses the geometric area for that shape and then multiplies by average depth.
2) Enter dimensions
Use metres or feet based on your selected unit system. Keep all dimensions in the same unit for accuracy.
3) Enter depth
You can use a single uniform depth, or enter both shallow and deep ends. For sloped pools, average depth is calculated automatically:
- Average depth = (shallow depth + deep depth) ÷ 2
4) Get results in multiple units
The output includes litres, cubic metres, US gallons, and UK gallons so you can match local labels and treatment guides.
Pool volume formulas used
Rectangular pool litres
- Volume = length × width × average depth
- If metric, result is in m³ then converted to litres (× 1000)
Circular pool litres
- Area = π × (diameter ÷ 2)²
- Volume = area × average depth
Oval pool litres
- Area = π × (length ÷ 2) × (width ÷ 2)
- Volume = area × average depth
Tips for better accuracy
- Measure internal waterline dimensions, not outside deck dimensions.
- Take depth readings at several points if the floor is uneven.
- For freeform pools, break the shape into sections and estimate each part.
- Re-check litres after major renovation or resurfacing.
Using litres for pool chemicals
Most chemical labels provide dose rates per 10,000 litres, 50,000 litres, or per 1,000 gallons. Once your pool litre estimate is known, dosing becomes straightforward. Example:
- If product says 100 ml per 10,000 litres and your pool is 45,000 litres, start with 450 ml.
- Circulate water and retest before adding more.
Always follow manufacturer instructions and local safety guidelines. This page provides a volume estimate, not chemical treatment advice.
Common questions
Is this the same as a pool gallon calculator?
Yes. It functions as both a pool litre calculator and a pool gallon calculator because results are shown in litres and gallons.
Can I calculate spa or hot tub volume?
Yes, as long as the shape is close to rectangular, circular, or oval. For complex benches and contours, treat the result as an estimate.
What if my pool has a variable floor profile?
Use the shallow and deep depth option, or calculate in segments and add totals. Segmenting usually gives the best real-world estimate for irregular designs.
Final note
This pool litre calculator gives a practical estimate for everyday maintenance. For engineering-level precision, especially on large commercial pools, request a professional volume verification. For most homeowners, this calculator provides an accurate and useful starting point for balancing and care.