Volume converter
Convert between litres, millilitres, cubic metres, US gallons, quarts, cups and fluid ounces — for cooking, fuel and shipping.
US customary volumes unless the label says imperial; results rounded to three decimals.
How this calculator works
Volume conversions are full of traps because several “gallon”, “pint” and “ounce” units exist. A US liquid gallon is 3.78541 litres; an imperial (UK) gallon is 4.54609 litres — about 20% larger. A US pint is 473.18 mL, while a UK pint is 568.26 mL, which is why a British beer glass and an American pint are different sizes. The fluid ounce is a volume unit unrelated in size to the ounce of mass.
For cooking, US recipes use cups of 236.59 mL and fluid ounces of 29.57 mL. For fuel, most of the world sells petrol by the litre while the US uses gallons, which is why fuel-economy figures need converting too. For shipping and storage, cubic metres are standard: one cubic metre is 1,000 litres. This calculator uses US customary volumes unless the unit label says otherwise; convert imperial values with the labels provided.
The formula
Convert to litres, then to the target unit:
L = value × factor(from)
result = L / factor(to)
1 US gal = 3.785411784 L 1 imp gal = 4.54609 L
1 US qt = 0.946352946 L 1 US cup = 0.2365882365 L
1 US fl oz = 0.0295735296 L 1 m³ = 1,000 LSo 10 L = 2.642 US gallons = 10.567 US quarts = 42.268 US cups = 338.14 US fl oz.
Worked example
Converting 10 Litres gives 2.642 US gal in US gallons, 10.567 US qt in US quarts and 42.268 US cup in US cups — 338.140 US fl oz in fluid ounces.
Common mistakes
- Mixing US and imperial gallons. An imperial gallon is 20% larger than a US gallon. Fuel economy and beer sizes are the usual casualties.
- Confusing fluid ounces with ounces of weight. A fluid ounce measures volume; an ounce (28.35 g) measures mass. They are not interchangeable.
- Rounding cups in recipes. One cup is 236.6 mL, not 250 mL. For baking, small errors change texture, so use millilitres for accuracy.
Frequently asked questions
How many litres in a gallon?
A US gallon is 3.785 litres; an imperial gallon is 4.546 litres. Check which gallon a recipe or fuel figure uses.
How many cups in a litre?
One litre is 4.227 US cups (236.6 mL each) or about 3.52 UK/imperial cups (284 mL each).
How many millilitres in a US fluid ounce?
One US fluid ounce is 29.574 mL. An imperial fluid ounce is 28.413 mL, which is why UK cookbooks can differ slightly.
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