Litres to Gallons Conversion
Convert pool volume between litres, cubic metres, US gallons and imperial gallons using the official litre definitions.
· 7 min read
Pool chemicals, heaters and fill estimates all depend on volume, but labels do not agree on units. This page uses the official litre definitions so a US gallon and an imperial gallon are never mixed up.
The constants
1 US liquid gallon = 3.785411784 litres
1 imperial gallon = 4.54609 litres
To convert litres to US gallons, divide by 3.785411784 (or multiply by ≈ 0.264172). To convert litres to imperial gallons, divide by 4.54609 (or multiply by ≈ 0.219969).
Worked example
A rectangular pool of 8 m × 4 m × 1.5 m is 48 m³ = 48,000 litres.
- US gallons = 48,000 ÷ 3.785411784 ≈ 12,680
- Imperial gallons = 48,000 ÷ 4.54609 ≈ 10,559
Imperial gallons are larger, so the same pool is fewer imperial gallons than US gallons. Using a US dosing chart with an imperial figure (or the other way around) will under- or over-dose.
Quick reference
- 10,000 litres ≈ 2,642 US gal ≈ 2,200 imperial gal
- 25,000 litres ≈ 6,604 US gal ≈ 5,499 imperial gal
- 50,000 litres ≈ 13,209 US gal ≈ 10,998 imperial gal
- 100,000 litres ≈ 26,417 US gal ≈ 21,997 imperial gal
Which unit should you use?
Match the unit printed on the product. Most European and Australian sanitiser labels use litres or m³. US chlorine, algaecide and salt-cell manuals use US gallons. Older UK books sometimes still quote imperial gallons. The calculator always returns all four so you can pick the matching column.
If you still need the raw measurements, start with how to measure a pool and the volume formulas.