Volume converter for metric, US and imperial units
This volume converter handles 19 units: milliliters to cubic meters, cubic inches and feet, US kitchen measures, US and imperial pints and gallons, and the oil barrel. The key thing it helps with is keeping US and imperial measures apart, because units with the same name have different sizes.
US gallon versus imperial gallon
The US gallon is defined as 231 cubic inches, exactly 3.785411784 liters. The imperial gallon used in the UK is exactly 4.54609 liters, so 1 imperial gallon = 1.200949926 US gallons.
Fluid ounces run the opposite way. A US fluid ounce is 29.5735295625 mL and an imperial fluid ounce is 28.4130625 mL, because the US gallon holds 128 fluid ounces and the imperial gallon 160. The same split carries into pints: a US pint is 16 US fl oz (473.176473 mL), an imperial pint 20 imperial fl oz (568.26125 mL).
Which cup does the tool use?
The US cup here is the customary cup: 8 US fluid ounces, or 236.5882365 mL. It is not the only cup in circulation. US nutrition labels use a rounded 240 mL, and Australia and New Zealand use a 250 mL metric cup. If a recipe comes from one of those countries, a small difference per cup can add up over a large batch.
1 cup = 236.5882365 ml
1 cup = 16 tbsp
1 tbsp = 3 tsp
1 tbsp = 14.78676478 ml
1 tsp = 4.928921594 ml
1 l = 4.226752838 cupCubic units and the oil barrel
A liter is one cubic decimeter, so 1 L = 1000 cm³ and 1 m³ = 1000 L, which is 264.1720524 US gallons. One cubic foot holds 28.31684659 L, a figure that comes up with appliance capacities and aquariums.
Crude oil is traded in barrels of exactly 42 US gallons, or 158.987294928 liters. Other industries have used barrels of different sizes, so check that a figure really means an oil barrel before converting.
Common mistakes
- Fluid ounces versus ounces. A fluid ounce is volume; an ounce is mass. Only for water-like liquids are they roughly interchangeable. For mass, use the mass converter.
- British pints in US recipes. An imperial pint is 20% larger than a US pint.
- Metric sizes on labels. A 500 mL bottle is 16.90701135 US fl oz, not 16.
To turn a volume into a mass, multiply by density with help from the density converter. For car consumption figures that mix gallons and liters, the fuel economy converter handles both gallon types.