Volume Converter
Convert a volume between metric units, US liquid units (gallons, quarts, pints, cups, ounces, tablespoons, teaspoons), imperial units and cubic measures. US and imperial units are listed separately because they are not the same size.
Result
Enter a value to convert.
The calculation runs in this browser tab. Nothing you enter is uploaded, saved or logged.
Why are US and imperial volume units different?
The litre is the everyday metric unit: one litre is the volume of a cube 10 cm on each side, a thousandth of a cubic metre. Volumes in cooking and fuel are also given in the units derived from the gallon, but there are two gallons. The US gallon is defined as exactly 231 cubic inches, which is 3.785411784 litres. The imperial gallon, used in the United Kingdom, is defined as exactly 4.54609 litres, about 20% larger.
All the other US liquid units divide the US gallon: 4 quarts, 8 pints, 16 cups, 128 fluid ounces. The imperial system divides its gallon into 4 quarts, 8 pints and 160 imperial fluid ounces, so the imperial pint (568 mL) is larger than the US pint (473 mL) while the imperial fluid ounce (28.41 mL) is slightly smaller than the US one (29.57 mL).
How to use the Volume Converter
- Enter the volume you want to convert. Negative values are not accepted.
- Choose the unit you are converting from and the unit you are converting to. Make sure to pick US or imperial correctly.
- Read the result, the conversion factor and its inverse. A leading ≈ means the value was rounded to the selected precision.
- Use the table to see the volume in every unit, and Copy result to copy the number alone.
Formula
- General rule
- result = value × (litres per source unit) ÷ (litres per target unit)
- US gallons to litres
- L = gal × 3.785411784
- Imperial gallons to litres
- L = gal × 4.54609
- Cubic feet to litres
- L = ft³ × 28.316846592
Whole-number relations among US units: 1 gallon = 4 quarts = 8 pints = 16 cups = 128 fluid ounces; 1 cup = 16 tablespoons = 48 teaspoons; 1 tablespoon = 3 teaspoons.
A cubic unit is the cube of a length unit: 1 ft³ = 0.3048³ m³ = 28.316846592 L, and 1 yd³ = 27 ft³.
Worked example
Three US gallons of fuel in litres. These are the results the converter gives:
| Question | Result |
|---|---|
| Input: Value | 3 |
| Input: From | US gallons (US gal) |
| Input: To | Litres (L) |
| Input: Precision | 10 significant digits |
| 3 US gal equals | ≈ 11.35623535 L |
| Conversion factor | 1 US gal = 3.785411784 L |
| Inverse | 1 L = ≈ 0.2641720524 US gal |
| Formula | L = US gal × 3.785411784 |
Assumptions and limits
- The cup, tablespoon and teaspoon are the US customary ones (236.588 mL, 14.787 mL and 4.929 mL). Nutrition labels in the US round them to 240 mL, 15 mL and 5 mL, and a metric cup is 250 mL; those variants are not included.
- Imperial units are listed separately. The UK stopped using them for most trade, but they remain in recipes, fuel economy and some packaging.
- These are liquid (fluid) measures. US dry measures such as the dry pint and bushel are different sizes and are not included.
- Results are shown to 6 to 15 significant digits; non-terminating conversions are rounded and marked ≈.
Frequently asked questions
How many litres are in a US gallon?
3.785411784 litres exactly. For a quick estimate use 3.785, or about 3.8 litres.
How many litres are in an imperial gallon?
4.54609 litres exactly. An imperial gallon is about 1.2 US gallons, so a car that does 40 miles per imperial gallon does about 33 miles per US gallon.
How many cups are in a gallon?
Sixteen US cups in a US gallon: 4 quarts of 4 cups each. That also means 128 US fluid ounces.
How many millilitres are in a cup, a tablespoon and a teaspoon?
A US customary cup is 236.588 mL, a tablespoon 14.787 mL and a teaspoon 4.929 mL. In practice recipes often use 240, 15 and 5 mL.
How do I convert cubic feet to litres?
Multiply by 28.316846592. A 3 ft³ freezer holds about 85 litres. A cubic foot is also about 7.48 US gallons.
Is a millilitre the same as a cubic centimetre?
Yes. One millilitre is exactly one cubic centimetre, and 1,000 mL make one litre. The converter lists them together.