UK Gallons to Liters Converter (imp gal to L)

The imperial gallon, defined in UK law as exactly 4.54609 L, is still the gallon behind British fuel economy figures, older engineering and plumbing references, and the casks that hold real ale. Fuel itself has been sold by the liter in the UK for decades, so converting gallons to liters is how a miles-per-gallon figure or an old spec sheet meets today's pumps and tanks.

A UK gallon holds 8 UK pints or 160 UK fluid ounces and is about 20% larger than the US gallon of 3.785411784 L. Older Canadian sources also use it, so check which gallon a figure means before converting; the table lists traditional British cask and dry measures that are multiples of it.

How to use this tool

1. Type a value in the UK Gallon box to see it in liters, or type in the Liter box to convert the other way.
2. Press ⇄ to swap the two units, or Load example for a typical value.
3. Check the charts below for common values; for other units, open the Volume converter.

Formula

Liter (L) = UK Gallon (imp gal) × 4.54609

UK Gallon (imp gal) = Liter (L) × 0.219969248299

Both factors come from exact definitions: 1 liter = 0.219969248299 UK gallons and 1 uk gallon = 4.54609 liters (shown to 12 significant digits).

Example

Two conversions worked with the same factors the converter uses:

9 imp gal × 4.54609 = 40.91481 L

30 L × 0.219969248299 ≈ 6.59908 imp gal

UK Gallon to Liter chart

Common values from UK gallons to liters, rounded to four decimal places.

Liter to UK Gallon chart

The reverse direction for values people often look up.

Traditional British measures in imperial gallons

Quick mental estimate

Multiply by 4.5: 10 gal → 45 L. The exact answer is 45.46 L, so the shortcut comes out about 1% low; adding 1% fixes it.

Use the converter or the charts when the exact figure matters.

The two units

UK Gallon (imp gal): The UK (imperial) gallon is defined as exactly 4.54609 liters, about 20% larger than the US gallon. It is still used for fuel economy figures in the UK.

Liter (L): The liter is the metric unit of volume accepted for use with the SI. Since 1964 it has been defined as exactly one cubic decimeter, which is 1,000 cubic centimeters.