Liters ↔ Gallons Converter.

A US gallon is 3.785 litres while a UK imperial gallon is 4.546 litres — roughly 20% larger. American equipment is usually rated in US gallons, European in litres, and older UK hardware in imperial gallons. Mixing them up in dosing introduces a 20% error, which matters for medications and fertilisers.

Divide litres by 3.785 for US gallons or by 4.546 for UK gallons. As a mental shortcut, multiply litres by 0.264 to get US gallons. This converter does the exact conversion in both directions, so if you know your tank in litres you can read the US-gallon figure instantly.

Fresh water weighs about 8.34 pounds per US gallon, or 1 kilogram per litre. Saltwater is slightly denser at roughly 8.55 pounds per gallon. The converter reports water weight alongside each conversion so you can sanity-check floor loads without jumping to another tool.

No. Canada officially uses litres, and no separate Canadian gallon unit exists. Canadian-bought tanks and equipment are labelled in litres and US gallons, so the conversions above are the only ones you need.

For planning purposes — choosing a tank, sizing a filter — rounding to whole gallons or litres is fine. For dosing medications and fertilisers, keep at least one decimal place: a 20% UK/US gallon mix-up or a 0.5 gallon error on a small tank is enough to shift a dose.

Manufacturers serve global markets, so labels carry the figure in whichever units the target region uses, often both. When the two figures don't look proportional, the difference is usually US versus UK gallons, not an error in the tank.