Convert volume and capacity units

This volume converter handles metric units (millilitres, litres, cubic metres) and both US and UK liquid measures (fluid ounces, cups, pints, quarts, gallons). Because US and UK gallons and pints are different sizes, the converter keeps them separate so your results are always accurate — especially useful for following recipes from another country.

US vs UK measures

A US gallon is about 3.785 litres, while a UK (imperial) gallon is larger at about 4.546 litres. Pints differ too: a US pint is 473 ml and a UK pint is 568 ml. This is why a recipe’s “pint of milk” can mean different amounts depending on where it was written. Always check which system a recipe uses.

Common volume conversions

From	To	Result
1 litre	US gallons	0.264 gal
1 US gallon	litres	3.785 l
1 UK gallon	litres	4.546 l
1 US cup	millilitres	236.6 ml

How the volume conversion works

Every unit in this converter is stored as a fixed number of litres. When you enter a value, the tool multiplies it by the litre factor of the unit you are converting from, then divides by the litre factor of the unit you are converting to. The answer is shown to eight significant figures, which is far more precision than any kitchen jug or fuel pump needs, so round it to suit the job.

Result = value × (litres per “from” unit) ÷ (litres per “to” unit)

The factors come from exact legal definitions. The UK (imperial) gallon is defined as exactly 4.54609 litres. The US gallon is defined as 231 cubic inches, which works out at 3.785411784 litres. Smaller units are fixed fractions of those gallons: a UK pint is one eighth of a UK gallon and holds 20 UK fluid ounces, while a US pint is one eighth of a US gallon and holds 16 US fluid ounces.

Unit	Millilitres	How it is defined
US teaspoon	4.929 ml	1/6 US fl oz
US tablespoon	14.787 ml	3 US teaspoons
UK fluid ounce	28.413 ml	1/160 UK gallon
US fluid ounce	29.574 ml	1/128 US gallon
US cup	236.588 ml	8 US fl oz
US pint	473.176 ml	16 US fl oz
UK pint	568.261 ml	20 UK fl oz
US quart	946.353 ml	2 US pints
US gallon	3,785.41 ml	231 cubic inches
UK gallon	4,546.09 ml	exactly 4.54609 litres
Cubic metre	1,000,000 ml	1,000 litres

Worked examples

Example 1: 2 litres of stock to US cups

• 2 litres × 1 = 2 litres (litres are already the base unit)
• 2 ÷ 0.2365882 = 8.4535
• Answer: about 8.45 US cups, or roughly 8 and a half cups

Example 2: a 5 UK gallon water container in US gallons

• 5 × 4.54609 = 22.73045 litres
• 22.73045 ÷ 3.7854118 = 6.0047
• Answer: about 6.00 US gallons. Five imperial gallons hold almost exactly six US gallons, a handy pairing to remember.

Example 3: a 330 ml can in fluid ounces

• 330 ml × 0.001 = 0.33 litres
• US: 0.33 ÷ 0.0295735 = 11.16 US fl oz
• UK: 0.33 ÷ 0.0284131 = 11.61 UK fl oz
• Answer: the same can is about 11.2 fl oz in the US and 11.6 fl oz in the UK, because the UK fluid ounce is slightly smaller.

Example 4: a 200 litre water butt

• 200 ÷ 4.54609 = 43.99 UK gallons
• 200 ÷ 3.7854118 = 52.83 US gallons
• 200 ÷ 1,000 = 0.2 cubic metres

Quick mental shortcuts

• 1 litre is about 1.76 UK pints or 2.11 US pints.
• 1 litre is about 1.06 US quarts, so a litre bottle is “a quart and a bit”.
• 1 US gallon is about 3.8 litres; 1 UK gallon is about 4.5 litres.
• 1 UK gallon is about 1.2 US gallons, so 5 UK gallons is about 6 US gallons.
• 1 cubic metre is 1,000 litres, about 220 UK gallons or 264 US gallons.
• 1 US cup is just under 240 ml; 4 cups is a little less than a litre.

Common mistakes to avoid

• Assuming UK units are always bigger. The UK pint and gallon are larger than the US ones, but the UK fluid ounce (28.4 ml) is smaller than the US fluid ounce (29.6 ml). The UK pint is bigger only because it contains 20 ounces instead of 16.
• Mixing liquid and dry measures. This converter uses US liquid pints and quarts. The US also has a separate dry pint of about 551 ml, used for things like berries, which is around 16% larger than the liquid pint.
• Converting volume when a recipe needs weight. A cup of flour and a cup of sugar have the same volume but very different weights. For baking, see our guide to converting cups to grams for flour, sugar and butter.
• Using US spoons for UK or Australian recipes. UK recipes use metric spoons of 5 ml and 15 ml, and an Australian tablespoon is 20 ml. Convert these as millilitres rather than US spoons.
• Nutrition label cups. US food labels round the cup to 240 ml for serving sizes, while the customary US cup in this converter is 236.6 ml. The gap is small but adds up over large batches.

Where each unit is used: UK vs US

In the UK, almost everything is sold in litres and millilitres, but the pint survives for draught beer, cider and doorstep milk, and fuel economy is still quoted in miles per UK gallon even though petrol is priced per litre. Household water meters record cubic metres. In the US, customary units dominate everyday life: fuel and milk are sold by the gallon, drinks by the fluid ounce, and recipes by cups, tablespoons and teaspoons. Science, medicine and most manufacturing on both sides of the Atlantic use millilitres, litres and cubic metres. For a deeper look at fuel and mpg, read UK gallons vs US gallons and why the litre conversion differs.

Frequently asked questions

How many millilitres in a litre?

There are 1,000 millilitres in one litre.

Is a US cup the same as a UK cup?

Not quite. A US cup is about 237 ml, while a metric cup (used in the UK and Australia) is 250 ml. For precise baking, use the right measure for your recipe.

How many US cups are in a litre?

There are about 4.23 US cups in one litre (1 ÷ 0.2365882). If you are using 250 ml metric cups, a litre is exactly 4 cups.

How many UK pints are in a US gallon?

A US gallon (3.785 litres) holds about 6.66 UK pints, compared with 8 US pints. A UK gallon holds exactly 8 UK pints.

Why is a UK pint bigger when a UK fluid ounce is smaller?

A UK pint contains 20 UK fluid ounces of 28.41 ml each (568 ml in total), while a US pint contains only 16 US fluid ounces of 29.57 ml each (473 ml). The extra four ounces more than make up for the smaller ounce.

Related volume tools

Working in cubic feet or cubic yards for a building or garden job? Use the cubic metre, foot and yard converter. For recipe spoons and cups by ingredient, try the cooking measurement converter, and if you need litres per minute or gallons per minute, the flow rate converter handles volume over time. To work out how much water a pool holds in the first place, see the pool volume calculator.