Volume Converter

About the Volume Converter

A volume converter transforms between metric (millilitres, litres, cubic centimetres, cubic metres), US customary (US fluid ounces, US cups, US pints, US quarts, US gallons), and imperial (UK fluid ounces, UK pints, UK gallons) volume units, plus cubic feet, cubic inches, and specialised units like barrels (oil industry) and bushels (grain trade). Volume conversion is essential for cooking with international recipes, understanding fuel economy comparisons between countries, calculating tank and container capacities, medical liquid dosing, and international trade. One of the most consequential volume conversion mistakes: confusing US and UK gallons. A US gallon = 3.785 litres; a UK Imperial gallon = 4.546 litres — a 20% difference that causes significant errors in fuel calculations, recipe scaling, and shipping documentation if the wrong gallon is used.

How It Works

Base unit: litre (L) = 1,000 mL = 0.001 m³. Key conversions: 1 US gallon = 3.78541 L = 4 US quarts = 8 US pints = 16 US cups = 128 US fl oz. 1 UK gallon = 4.54609 L = 8 UK pints = 160 UK fl oz. 1 L = 0.264172 US gallons = 0.219969 UK gallons = 33.814 US fl oz. 1 US fl oz = 29.5735 mL. 1 UK fl oz = 28.4131 mL. 1 cubic foot = 28.3168 L = 7.48052 US gallons. 1 US cup = 236.588 mL = 8 US fl oz. 1 tablespoon = 14.787 mL = 3 teaspoons = 0.5 fl oz. 1 petroleum barrel = 42 US gallons = 158.987 L.

Tips & Best Practices

• ✓US versus UK: a US recipe calling for 1 gallon of liquid uses 3.785 L; a UK recipe uses 4.546 L — always check which country a recipe originates from before converting.
• ✓Fuel economy: to convert US mpg to L/100km: divide 235.215 by mpg. 30 US mpg = 235.215/30 = 7.84 L/100km. To convert L/100km to mpg: 235.215 / L/100km.
• ✓Cooking measurements: 1 teaspoon = 5 mL; 1 tablespoon = 15 mL; 1 US cup = 240 mL (approximately — officially 236.588 mL); 1 litre ≈ 4.23 US cups.
• ✓Standard wine bottle: 750 mL = 25.36 US fl oz ≈ 5 glasses at 150 mL each. A magnum = 1.5 L = 2 standard bottles.
• ✓Aquarium sizing: a 10-gallon (US) aquarium = 37.85 litres. A 55-gallon = 208.2 litres. UK gallons give larger numbers for the same tank.
• ✓Oil barrel: 1 barrel of crude oil = 42 US gallons = 158.987 litres. Oil prices quoted per barrel on international markets.
• ✓Pool volume: an Olympic-size swimming pool = 2,500 m³ = 2,500,000 litres = 660,430 US gallons. Residential pools: 40,000-100,000 litres (10,500-26,400 US gallons) for a standard backyard pool.
• ✓Medical dosing: liquid medications are dosed in mL (international standard). 1 teaspoon = 5 mL is the standard conversion for over-the-counter liquid medications in the USA.

Who Uses This Calculator

Home cooks converting between US cups/teaspoons and metric mL/grams for international recipes. Travellers understanding fuel economy and tank size when driving in countries with different unit systems. Homebrewers and winemakers scaling recipes between gallons and litres. Medical professionals measuring and administering liquid medications. Pool owners calculating chemical dosing for their specific pool volume. International trade professionals converting liquid cargo volumes between measurement systems. Aquarium hobbyists stocking tanks with appropriate fish densities based on volume.