Volume Converter - Litres, Millilitres, Cups, Pints, Quarts and Gallons (US and Imperial)

Every volume is held as an exact fraction of a cubic metre. A cubic unit uses the cube of its length factor, so 1 cubic inch is exactly 0.0254 x 0.0254 x 0.0254 m³, which is 16.387064 mL. Conversions use whole numbers rather than floating point, so a conversion followed by its reverse returns the number you typed. The answer is rounded only when it is shown: Auto shows an exact result in full when it fits in 14 digits and otherwise rounds to 10 significant digits.

The US liquid units all come from the gallon, which is defined as 231 cubic inches, exactly 3.785411784 L. A quart is 1/4 gallon (946.352946 mL), a pint is 1/8 (473.176473 mL), a cup is 1/16 or 8 fluid ounces (236.5882365 mL) and a fluid ounce is 1/128 (29.5735295625 mL). A tablespoon is half a fluid ounce and a teaspoon is a third of a tablespoon. NIST Handbook 44 lists these relations.

The imperial gallon is exactly 4.54609 L in the UK Weights and Measures Act 1985, and NIST SP 811 gives the same figure. An imperial quart is 1/4 of it, a pint is 1/8 (568.26125 mL) and a fluid ounce is 1/160 (28.4130625 mL). So an imperial pint holds 20 fluid ounces and a US pint holds 16. NIST describes the imperial gallon as about 20 percent larger than the US gallon, and the exact ratio is 1.200949926. An imperial fluid ounce is slightly smaller than a US one.

A litre is one cubic decimetre, so 1 L is 1,000 cm³ and 1 mL is 1 cm³. This converter uses the US customary cup and spoons. NIST calls the cup, tablespoon and teaspoon measuring units and rounds them to 237, 15 and 5 mL. Recipes in Australia, Canada and New Zealand use a 250 mL metric cup, and US nutrition labels define a cup as 240 mL, so check which one a recipe means. For baking, weighing the ingredients is more reliable than measuring by volume.