Convert any volume to every common unit at once: litres and millilitres, US and UK gallons, pints, cups and spoons, cubic feet and metres, and barrels.
1 US gallon = 3.785 L · 1 UK gallon = 4.546 L
Most volume mix-ups come from units that share a name. A UK pint is 20% bigger than a US pint, but a UK fluid ounce is slightly smaller than a US one, because the UK pint holds 20 fluid ounces against the US pint's 16. Check where a recipe or spec comes from before converting.
| Unit | US (mL) | UK (mL) | Metric (mL) |
|---|---|---|---|
| Teaspoon | 4.928922 | 5.919388 | 5 |
| Tablespoon | 14.786765 | 17.758164 | 15 |
| Fluid ounce | 29.57353 | 28.413062 | — |
| Cup | 236.588236 | 284.130625 | 250 |
| Pint | 473.176473 | 568.26125 | — |
| Gallon | 3,785.411784 | 4,546.09 | — |
The metric cup (250 mL) is used in Australia, New Zealand and Canada. Australia also uses a 20 mL tablespoon, unlike the 15 mL metric tablespoon used elsewhere.
Every unit has a fixed size in millilitres. To convert, multiply by the size of the unit you have, then divide by the size of the unit you want. The US gallon is defined as exactly 231 cubic inches, and the UK gallon as exactly 4.54609 litres. All the other US and UK units are fractions of those.
For a box-shaped container, multiply the three inside dimensions. Measure all three in the same unit, then use the cubic result:
Cubing multiplies conversion factors too: 1 ft = 12 in, so 1 ft³ = 12 × 12 × 12 = 1,728 in³, not 12.
An aquarium measures 60 cm × 30 cm × 40 cm inside. Water treatment instructions are written per US gallon.
Step 1: Volume in cubic centimetres
Step 2: Litres
Step 3: US gallons
The tank holds 72 L, or about 19 US gallons (15.8 UK gallons) when full to the brim. Gravel and decorations take up space, so dose for the actual water volume, which is usually 10–20% less.
| Item | mL | Litres | US gallons |
|---|---|---|---|
| Medicine teaspoon | 5 | 0.005 | 0.001321 |
| US soda can (12 US fl oz) | 355 | 0.355 | 0.093781 |
| UK pint of beer | 568.26125 | 0.568261 | 0.150119 |
| Standard wine bottle | 750 | 0.75 | 0.198129 |
| US gallon of milk | 3,785.411784 | 3.785412 | 1 |
| Oil barrel | 158,987.294928 | 158.987295 | 42 |
| Olympic swimming pool (minimum) | 2.5 × 10⁹ | 2,500,000 | 660,430.130895 |
A litre of water weighs about 1 kg, which is why the two are often treated as interchangeable. Other liquids differ: a litre of cooking oil weighs about 0.92 kg and a litre of honey about 1.4 kg. Dry ingredients vary even more with how tightly they're packed. To convert volume to weight you need the substance's density, not just a volume converter.
3.785 litres in a US gallon and 4.546 litres in a UK (imperial) gallon. The UK gallon is about 20% larger.
Yes. One millilitre is exactly one cubic centimetre. Medicine often writes it as "cc".
The two systems were defined from different gallons. A UK fluid ounce is 1/160 of a UK gallon (28.41 mL), and a US fluid ounce is 1/128 of a US gallon (29.57 mL).
About 4.23. A US cup is 236.6 mL, and 1,000 ÷ 236.6 ≈ 4.23.
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