Free online volume converter. Convert gallons to liters, cups to milliliters, fluid ounces to liters, pints, quarts, and 10+ more units — instant results with visual comparison.
US • Imperial • Metric • 11 units
Convert gas tank size and fuel economy between US gallons, UK gallons, and liters.
Convert between cups, tablespoons, teaspoons, and milliliters for any recipe.
Compare product sizes labeled in different units when buying from international sellers.
Volume conversions are among the most searched in the United States because of the gap between US customary units (gallons, quarts, pints, cups, fluid ounces) and the metric system (liters, milliliters). This comes up constantly in cooking, fuel purchases, home brewing, aquarium setup, and shopping from international retailers.
Key volume facts: 1 US gallon = 3.78541 liters = 4 quarts = 8 pints = 16 cups = 128 fluid ounces. 1 US cup = 236.588 mL = 8 fluid ounces = 16 tablespoons = 48 teaspoons. 1 fluid ounce = 29.5735 mL. 1 liter = 33.814 US fluid ounces = 4.227 cups. Note: the UK pint = 568 mL, while the US pint = 473 mL — 20% larger in the UK.
1 US gal = 3.785 L. 10 gal = 37.85 L. 20 gal = 75.7 L. Gas tank: 12 gal = 45.4 L. 15 gal = 56.8 L. 20 gal = 75.7 L. UK gal = 4.546 L (20% larger).
1 cup = 236.6 mL. ½ cup = 118.3 mL. ¼ cup = 59.1 mL. 1 tbsp = 14.79 mL. 1 tsp = 4.93 mL. 1 fl oz = 29.57 mL. 1 pint = 473.2 mL = 2 cups.
10-gal tank = 37.85 L. 20-gal = 75.7 L. 55-gal = 208 L. Average pool = 15,000 gal = 56,775 L. Hot tub = 400 gal = 1,514 L.
12 fl oz can = 354.9 mL. 16 fl oz pint = 473 mL. 20 fl oz = 591 mL. 1 liter bottle = 33.8 fl oz. 2-liter = 67.6 fl oz = 8.45 cups.
Volume carries the worst unit trap in everyday measurement: the US gallon and the imperial gallon are different sizes. The US liquid gallon is 3.785411784 litres, derived from the old English wine gallon, while the imperial gallon adopted in 1824 is 4.54609 litres — about 20% larger. Every unit beneath them inherits the discrepancy, so a US pint is 473 ml and an imperial pint is 568 ml. Fuel economy figures, recipe volumes and beer measures all break silently when the two systems are mixed, which is why "gallons" alone is never a sufficient specification.
litres = value × factor_fromresult = litres ÷ factor_toUS gal = 3.785411784 L · Imperial gal = 4.54609 L · US cup = 236.5882365 mLwhere:
Assumptions: US customary units by default. The US dry gallon (4.405 L) is a separate unit used for produce and is not interchangeable with the liquid gallon.
The same "12 gallons" in US and imperial measure, to show how far apart they land.
Result12 US gal = 45.43 L; 12 imperial gal = 54.55 L
This is why US and UK MPG figures cannot be compared directly: 40 imperial MPG is only about 33 US MPG for the identical car. Any cross-market fuel comparison must be converted before it means anything.