Volume converter - litres, gallons, cups and cubic metres

The litre is a metric unit accepted for use with the International System of Units. One litre equals 1,000 millilitres and exactly one cubic decimetre. A cubic metre contains 1,000 litres, making it useful for water tanks, pools and large quantities. One millilitre is also equal in volume to one cubic centimetre.

For example, a 750 ml bottle holds 0.75 litres, while a 2.5 m³ tank holds 2,500 litres. These relationships are decimal and straightforward, but remember that volume is not mass. A litre of water has a mass close to one kilogram under ordinary conditions, while a litre of oil, flour or another material has a different mass because its density differs.

The word gallon refers to two distinct units. A US liquid gallon is exactly 3.785411784 litres. An imperial gallon used in the UK is exactly 4.54609 litres, about 20% larger. A US gallon contains four US quarts or eight US pints; an imperial gallon contains four imperial quarts or eight imperial pints. Always check which system a fuel economy figure, recipe or container uses.

As an example, 10 US gallons equal about 37.85 litres, whereas 10 UK gallons equal about 45.46 litres. Fluid ounces also differ: one US fluid ounce is about 29.57 ml and one imperial fluid ounce is about 28.41 ml. The converter labels these standards separately to help prevent a mismatch when following a recipe or comparing product sizes.

Recipes may use metric millilitres, US cups or imperial measures. A US customary cup is 236.588 ml, while a metric cup is commonly defined as 250 ml. This difference can affect a recipe, especially when several cups of liquid are involved. A US pint is 473.176 ml; an imperial pint is 568.261 ml. A tablespoon can also vary by convention, so follow the measure system used by the recipe.

When accuracy matters, use the exact unit named by the source or measure in millilitres. For cooking, a measuring jug is more dependable than treating a drinking glass as a standard cup. For fuel, chemicals or regulated goods, use the unit printed on the official label. This tool performs a numerical conversion and does not account for temperature expansion, ingredient density or container markings.