Volume Converter

How it works

Every unit here is defined as an exact number of cubic metres. The litre is one cubic decimetre, so 1,000 L make a cubic metre and 1,000 mL make a litre. The cubic inch, foot and yard are the cubes of the 1959 length definitions: one cubic inch is exactly 16.387064 mL.

The US liquid gallon is defined as 231 cubic inches, which makes it exactly 3.785411784 L. The smaller US liquid measures are fixed fractions of the gallon: 4 quarts, 8 pints, 16 cups or 128 fluid ounces. So a cup is 8 fl oz and a fluid ounce is 29.5735 mL. The imperial (UK) gallon is a separate unit defined as exactly 4.54609 L, about 20% larger than the US gallon.

The calculator multiplies your value by the size of the from unit in cubic metres, then divides by the size of the to unit. The factor shown is what one from unit equals in the to unit. Results are rounded to six decimal places for display only.

Formula

cubic metres = value × m³ per from unit
result       = cubic metres ÷ m³ per to unit
factor       = m³ per from unit ÷ m³ per to unit
1 L = 1 dm³   1 cu in = 16.387064 mL   1 US gal = 231 cu in = 3.785411784 L   (exact)
1 gal = 4 qt = 8 pt = 16 cups = 128 fl oz   1 imp gal = 4.54609 L (exact)

Example

The default, 1 US gallon to litres: 231 cu in × 16.387064 mL = 3,785.411784 mL = 3.785412 L. The factor is 3.785412 L per gallon.

1 cubic foot to gallons is 1,728 ÷ 231 = 7.480519 gal. 1 litre is 33.814023 US fluid ounces, and a 5 gallon bucket holds 18.927059 L. An imperial gallon is 4.54609 L, or 4.54609 ÷ 3.785411784 = 1.200950 US gallons.

Assumptions and limitations

• Units use the exact legal definitions: the litre as a cubic decimetre (SI Brochure Table 8), the 1959 international yard and pound agreement for the cubic inch, foot and yard, and the US liquid gallon of 231 cubic inches (NIST Handbook 44, Appendix C).
• Fluid ounces, cups, pints, quarts and gallons are US liquid measures; the imperial gallon is offered as a separate unit. Imperial pints and fluid ounces (20 to the imperial pint, so not 1/128 of the imperial gallon) and the US dry pint and quart are different units and are not included. The US "legal" nutrition-label cup of 240 mL is not the customary cup of 236.588 mL used here.
• A negative value converts with its sign kept, so a change in volume can be converted as well as a volume.
• Results are rounded to six decimal places for display; the arithmetic is done in full double precision.

Frequently asked questions