What the volume converter does
The volume converter changes a value between fifteen units: milliliter (mL), liter (L), cubic centimeter (cm³), cubic meter (m³), cubic inch (in³), cubic foot (ft³), cup, US pint (pt), US quart (qt), US gallon (gal), US fluid ounce (fl oz), tablespoon (tbsp), teaspoon (tsp), imperial gallon (imp gal) and imperial pint (imp pt). Typing in either card updates the other card and the All Units list.
The metric side is decimal and exact: 1 L = 1,000 mL = 1 dm³, 1 m³ = 1,000 L, and a cubic centimeter is the same size as a milliliter. The US units are exact subdivisions of one gallon: 1 gal = 4 qt = 8 pt = 16 cups = 128 fl oz, 1 cup = 8 fl oz, and 1 fl oz = 2 tbsp = 6 tsp. One US gallon is 231 in³ = 3.785411784 L. The imperial units stand apart: 1 imp gal = 4.54609 L and 1 imp pt = 568.26125 mL.
For length and mass use the length converter and the weight converter; for typed arithmetic, the scientific calculator.
Background
In the SI the litre is exactly a cubic decimetre, so 1 L = 1,000 cm³ and a millilitre is a cubic centimetre; the cubic metre is the coherent unit and 1 m³ = 1,000 L. The US gallon is the older British wine gallon of 231 cubic inches, and the smaller US units are its subdivisions. Since 1959 one inch is exactly 25.4 mm, which makes 1 in³ = 16.387064 mL and a US gallon exactly 3.785411784 L. UK law defines the imperial gallon as 4.54609 dm³, divided into eight imperial pints of 20 imperial fluid ounces each (568.26125 mL); the converter offers the imperial gallon and pint but not the imperial fluid ounce.
Reading results and limits
- Display rule.
- Results carry up to 12 significant digits. Between 10⁻¹⁰ and 10¹⁵ they print with comma grouping and at most 10 decimal places (
3,785.411784, 0.1774411774, 0.0000353147); at 10¹⁵ and above, and below 10⁻¹⁰, they switch to a six-decimal exponential form (1.000000e+15, 1.000000e-14); zero prints as 0; a result that overflows binary64, such as 1e308 cubic meters, prints ---. - Small values.
- Values below 1 are capped at 10 decimal places, so the small end is where precision visibly drops:
1 mL in cubic feet reads 0.0000353147 and 1 mL in US gallons 0.0002641721. The last visible digit can round too — three teaspoons make one tablespoon exactly, 14.78676478125 mL, and the Milliliter row reads 14.7867647812. - Enter settles the input.
- Enter settles the focused field to 12 significant digits without grouping, and the rows then convert that written number: while
1/3 in a cup is still live the Milliliter row reads 78.8627455, and after Enter it reads 78.8627454999.