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Volume Converter
Volume Converter
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How volume conversion works
Volume is where unit conversion goes wrong most often, because the United States and the United Kingdom use different sizes for units that share a name. A US gallon is 3.785 litres. An imperial gallon is 4.546 litres, 20% larger. A recipe, a fuel figure or a tank capacity that does not say which one it means is ambiguous by a fifth.
This converter uses US customary units, which is the convention on the web and in almost all recipes published in English online.
Formulas
US gallons to litres
L = gal × 3.785411784
US cups to millilitres
mL = cup × 236.5882365
US fluid ounces to millilitres
mL = fl oz × 29.5735295625
Worked examples
| From | To | Result |
|---|---|---|
| 1 cup | ml | 236.588 ml |
| 1 gallon | L | 3.78541 L |
| 2 L | quart | 2.11338 quart |
| 1 tbsp | ml | 14.7868 ml |
| 1 tsp | ml | 4.92892 ml |
| 500 ml | fl oz | 16.907 fl oz |
Results are computed with the same factors the converter above uses, rounded to six significant figures.
Kitchen volumes
| ml | tsp | tbsp | cup |
|---|---|---|---|
| 5 | 1.01442 | 0.33814 | 0.0211338 |
| 15 | 3.04326 | 1.01442 | 0.0634013 |
| 60 | 12.173 | 4.05768 | 0.253605 |
| 120 | 24.3461 | 8.11537 | 0.50721 |
| 240 | 48.6922 | 16.2307 | 1.01442 |
| 500 | 101.442 | 33.814 | 2.11338 |
| 1,000 | 202.884 | 67.628 | 4.22675 |
A US tablespoon is 3 teaspoons and a US cup is 16 tablespoons. Australian tablespoons are 20 mL, or 4 teaspoons, which is a real trap in Australian recipes.
Worth knowing
- 1 US gallon = 231 cubic inches exactly, which works out to 3.785 411 784 L.
- 1 imperial gallon = 4.546 09 L exactly. It is about 20% larger than the US gallon.
- The imperial fluid ounce (28.41 mL) is smaller than the US fluid ounce (29.57 mL), even though the imperial gallon is larger: an imperial gallon is 160 imperial fluid ounces where a US gallon is 128 US ones. You cannot reason about which container is bigger from the ounce count alone.
- There are two US cups. The customary cup used here is 236.588 mL. The "legal" cup used on US nutrition labels is exactly 240 mL, a 1.4% difference that matters when a label figure is scaled up.
Frequently asked questions
- Is a US gallon the same as a UK gallon?
- No, and the difference is large. A US gallon is 3.785 litres; an imperial gallon is 4.546 litres, about 20% more. Fuel economy figures in miles per gallon are therefore not comparable between US and UK sources without knowing which gallon is meant.
- How many millilitres are in a cup?
- A US customary cup is 236.588 millilitres, which most recipes round to 240. A metric cup as used in Australia and New Zealand is exactly 250 millilitres. A UK recipe cup, where one is used at all, is usually 250 millilitres as well.
- How many tablespoons are in a cup?
- Sixteen, in US measure. A US tablespoon is 3 teaspoons, so a cup is also 48 teaspoons. Australian recipes use a 20 millilitre tablespoon of 4 teaspoons, so an Australian cup is 12.5 tablespoons rather than 16.
- Can I convert cups of flour to grams with this tool?
- No, and no volume converter can. Volume-to-weight depends on what is in the cup: a cup of flour is about 120 grams while a cup of sugar is about 200. That conversion needs an ingredient density table rather than a unit factor.