Litres to Gallons Converter

Litres are the metric volume unit used at UK petrol pumps, on milk bottles and in almost every European recipe or product spec. US gallons are the volume unit you'll see on American fuel quotes, car manuals, large drinks containers and any imported product that hasn't been converted for the UK market.

The formula in plain English: divide the number of litres by 3.78541 to get US gallons. One US liquid gallon is defined as 231 cubic inches, which works out to exactly 3.785411784 litres. This converter uses US gallons by default — UK (imperial) gallons are a different size, 4.54609 litres, and produce a different answer.

Worked example. A 50-litre car fuel tank holds 50 ÷ 3.78541 ≈ 13.2 US gallons. The same tank in UK imperial gallons would be 50 ÷ 4.546 ≈ 11.0 imperial gallons — which is why UK and US mpg numbers aren't directly comparable. A 20-litre jerrycan is about 5.3 US gallons or 4.4 imperial gallons. A 2-litre bottle of fizzy drink is 0.53 US gallons — roughly half a US gallon jug.

Why this matters. US mpg figures look much worse than UK mpg even for identical cars, because the US gallon is smaller. A car doing "30 mpg" in the US is the same as 36 mpg in the UK — a 20% difference caused entirely by the gallon size, not the car. Buying fuel, hiring cars or importing products from the US without knowing this turns into a costly surprise.

When to use it. Comparing US and UK fuel economy figures, converting US recipe volumes, sizing imported aquariums or fuel cans, and reading large drink container labels that quote gallons.

When not to rely on it alone. If you're buying fuel or following a recipe in the UK, always work in litres directly — converting back and forth introduces rounding errors. The converter is for translation between systems, not for everyday UK use.

Common mistakes. Mixing US and UK gallons — they differ by 20%. Using "gallons" in a recipe without knowing which system the recipe assumed. Treating "fluid ounces" as 1/128 of a gallon in both systems (US: 1/128 of a US gal = 29.6 ml; UK: 1/160 of an imperial gal = 28.4 ml — close but not identical).