What this tool does
This converter handles the five UK volume units in everyday use: millilitres, litres, UK fluid ounces, UK pints, and UK gallons. Select a from-unit and a to-unit, enter a value, and the result updates instantly in your browser. All conversions go through millilitres as a common base.
The units explained
The millilitre (ml) is the SI base unit here — one thousandth of a litre, equal to one cubic centimetre (cc). The litre is 1,000 ml, the standard unit for drinks bottles, fuel, and cooking liquids.
The UK fluid ounce is exactly 1/20 of a UK pint, giving 28.4130625 ml. The UK pint is 568.26125 ml — the legal measure for draught beer and cider in British pubs. The UK gallon contains exactly 8 UK pints (4,546.09 ml) and is still used for fuel consumption figures quoted in miles per gallon (mpg).
UK pint vs US pint — why they differ
A UK pint is 568.26 ml; a US pint is 473.18 ml — roughly 20% smaller. The divergence traces back to the Weights and Measures Act 1824, when Britain redefined the gallon as the volume of exactly 10 lb of water at a fixed temperature, giving the 8-pint gallon its current value. The United States had already codified its own system before 1824 and never adopted the Imperial revision, so the two systems diverged permanently.
In practice this matters most when following American recipes: a US cup is 240 ml, while there is no standard Imperial cup. A US pint of cream is 473 ml; a UK pint of milk is 568 ml. This tool works with UK units throughout.
UK gallon vs US gallon
A UK gallon is 4,546.09 ml; a US gallon is 3,785.41 ml — about 20% less. Because miles-per-gallon figures quoted in UK car reviews use the larger UK gallon, a car that achieves 40 mpg UK would be rated only about 33 mpg US. When comparing fuel economy between UK and US sources, the difference matters.
Worked example
Take 1 UK pint:
1 UK pint × 568.26125 = 568.2613 ml
Each UK pint contains exactly 20 UK fluid ounces and 1/8 of a UK gallon. Working through millilitres keeps all conversions precise regardless of direction.
Common uses
- Pub measures: A pint of beer is 568 ml by law in the UK. A half is 284 ml.
- Cooking and baking: US recipes quote cups (240 ml) and US fluid ounces (29.57 ml) — not the same as UK fluid ounces (28.41 ml).
- Fuel and mpg: UK fuel prices are per litre; UK mpg uses the UK gallon (4,546 ml), so 1 UK mpg ≈ 0.354 km/l.
- Medicine: Liquid medicines use ml (5 ml per teaspoon by UK convention) — no ambiguity across countries.
- Dairy: Milk is sold in 568 ml (1 pint), 1,136 ml (2 pints), and 2,272 ml (4 pints) bottles in the UK.
Frequently asked
How many ml in a pint?
A UK pint is exactly 568.26125 ml. A US pint is 473.176 ml. This tool uses UK pints.
How many pints in a gallon?
Exactly 8 UK pints in a UK gallon. A UK gallon is 4,546.09 ml.
How many ml in a UK fluid ounce?
Exactly 28.4130625 ml. There are 20 UK fluid ounces in a UK pint.
Is a UK fluid ounce the same as a US fluid ounce?
No. A UK fluid ounce is 28.413 ml; a US fluid ounce is 29.574 ml — about 4% larger. Cocktail recipes from US sources will be slightly off if you substitute UK fl oz without adjusting.