How many liters are in one UK gallon?

One UK Imperial gallon equals exactly 4.54609 liters. This is the internationally agreed definition set by the Weights and Measures Act and adopted by the International Bureau of Weights and Measures.

What is the difference between a UK gallon and a US gallon?

The UK (Imperial) gallon equals 4.54609 liters, while the US liquid gallon equals only 3.785411784 liters. The Imperial gallon is roughly 20% larger than the US gallon, so always confirm which gallon is being used in a recipe, fuel spec, or label.

How do I convert liters back to UK gallons?

Divide the liter value by 4.54609 (or multiply by 0.219969). For example, 10 liters ÷ 4.54609 ≈ 2.200 UK gallons.

Is this tool accurate enough for official or scientific use?

Yes. The conversion factor 4.54609 is the exact legally defined value. Results are displayed to six decimal places, which exceeds the precision needed for most practical and regulatory applications.

Why is the Imperial gallon larger than the US gallon?

The US gallon was derived from the older Queen Anne wine gallon (231 cubic inches), while the Imperial gallon was redefined in 1824 as the volume of 10 pounds of water at a specific temperature. The two systems diverged historically and are now distinct measurements.

UK Gallons to Liters Converter

Name: UK Gallons to Liters Converter
Availability: InStock
Author: Nham Vu

Enter a UK (Imperial) gallon value and instantly get the equivalent in liters, plus a handy reference table.

Enter UK Gallons

UK Imperial Gallons (gal)

Quick Reference Table

UK Gallons	Liters

Copied!

Summary

Enter a UK (Imperial) gallon value and instantly get the equivalent in liters, plus a handy reference table.

How it works

Enter a value in UK (Imperial) gallons in the input field.
The converter multiplies your input by 4.54609 (the exact internationally defined conversion factor).
The result in liters appears instantly.
Use the reference table below to look up common UK gallon-to-liter values at a glance.

Use cases

Convert fuel tank capacity from Imperial gallons to liters when traveling in metric countries.
Adjust recipe or beverage volumes when switching between UK and metric measurements.
Calculate heating oil or water storage tank volumes in liters.
Convert garden irrigation or watering quantities for metric sprinkler systems.
Check fuel efficiency figures (mpg) against liters-per-100km equivalents.
Verify import/export labeling when UK liquid volumes must be expressed in liters.

Frequently Asked Questions

Last updated: 2026-06-11 · Reviewed by Nham Vu