Volume Converter
Convert liquid volumes between liters, milliliters, US gallons, quarts, pints, cups, fluid ounces, spoons and the imperial gallon.
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This converter translates liquid and container volumes between liters and milliliters, US customary units (gallon, quart, pint, cup, fluid ounce, tablespoon, teaspoon) and the British imperial gallon. Pick the unit printed on your bottle, tank or recipe and every other unit appears beside it.
Volume is the measurement where the US and the UK disagree most. Both countries say gallon, pint and fluid ounce, yet a UK gallon holds about 20 percent more than a US gallon and a UK pint of beer is 568 mL against 473 mL for a US pint. Fuel economy, recipes and drink sizes copied from one country’s source to another are where these mismatches usually cause trouble, so the US and imperial gallons are listed separately rather than as a single "gallon".
The formula
- liters per source unit
- Liters in one of the units you typed, for example 0.2365882365 for a US cup
- liters per target unit
- Liters in one of the units you want to read
- in³
- Cubic inch, exactly 16.387064 cm³ because the inch is exactly 2.54 cm
The US gallon descends from the English wine gallon, which was fixed at 231 cubic inches in 1707. Since the inch is exactly 2.54 cm, that gallon is exactly 3.785411784 liters, and every smaller US unit is a clean fraction of it: a quart is a quarter, a cup a sixteenth, a fluid ounce a 128th.
Britain replaced its various gallons in 1824 with the imperial gallon, originally the volume of 10 pounds of water, and now defined as exactly 4.54609 liters. Because the imperial pint holds 20 imperial fluid ounces instead of 16, the imperial fluid ounce (28.41 mL) is actually slightly smaller than the US one (29.57 mL), even though the imperial gallon is larger. The liter itself is simply one cubic decimeter, 1,000 cm³.
Worked example
Carlos is renting a car in Scotland and his US owner’s manual says his own car’s tank holds 13.2 gallons. He wants to compare it with the rental’s tank listed in liters and with UK pump signs that still mention gallons.
- 1 Convert US gallons to liters: 13.2 × 3.785411784 = 49.9674 L.
- 2 Convert those liters to imperial gallons: 49.9674 ÷ 4.54609 = 10.9913 UK gal.
- 3 Compare the two gallon figures: 13.2 US gal and 10.99 UK gal describe the same tank, a difference of 2.2 "gallons".
Result: His tank holds about 50 liters, which is 13.2 US gallons but only 11.0 UK gallons. The same mismatch explains why UK miles-per-gallon figures look about 20 percent better than US figures for the same car.
Before you rely on the result
- US dry measures (the dry pint, peck and bushel) and imperial quarts, pints and fluid ounces are not included; only the imperial gallon is offered on the UK side.
- Liquid volume changes slightly with temperature, so fuel and industrial volumes are sometimes corrected to a reference temperature that this converter does not apply.
Frequently asked questions
Is a cup on a nutrition label the same as a measuring cup?
Not quite. A US customary cup is 236.6 mL, but US nutrition labels round the cup to 240 mL for serving sizes. Australia, Canada and New Zealand often use a 250 mL metric cup in recipes. For baking, check which cup the recipe author meant; a gap of 1 to 6 percent rarely ruins a stew, but it can upset bread dough hydration.
How many milliliters are in a teaspoon of medicine?
A US teaspoon is 4.93 mL, and pharmacies and dosing syringes treat it as 5 mL. Kitchen spoons vary widely in size, which is why health agencies recommend using the oral syringe or dosing cup that comes with the medicine rather than a household spoon.
Can I convert liters of flour into grams here?
No. Liters and cups measure space, grams measure mass, and the link between them is the ingredient’s density. A cup of water weighs about 237 g but a cup of all-purpose flour only around 120 to 130 g, depending on how it is packed. Use a cooking or recipe converter for ingredient weights.
Why does a 2-liter bottle not equal half a gallon?
Half a US gallon is 1.893 liters, so a 2-liter soda bottle holds about 5.7 percent more. Packaging in the US often lists both figures, such as 2 L (67.6 fl oz).