Volume Converter
Convert volume between litres, millilitres, cubic metres, US/UK gallons, quarts, pints, cups and fluid ounces — instantly, in both directions.
How volume conversion works
Every unit here is defined in litres (one litre = one cubic decimetre), so any conversion goes through the
litre in two exact steps. The key definitions:
- 1 US gallon = 3.785411784 L = 4 quarts = 8 pints = 128 US fl oz (exact)
- 1 UK gallon = 4.54609 L exactly — about 20% larger than the US gallon
- 1 US cup = 236.588 ml · 1 tablespoon = 14.787 ml · 1 teaspoon = 4.929 ml
- 1 m³ = 1,000 L
The US/UK split matters most for fuel economy and recipes: “miles per gallon” means different things on each
side of the Atlantic, and an American pint (473 ml) is smaller than a British one (568 ml).
Handy approximations
- litres → US gallons: multiply by 0.264, or divide by 3.8 (10 L ≈ 2.6 gal)
- US gallons → litres: multiply by 3.8 (5 gal ≈ 19 L)
- cups → ml: multiply by 237, or use 240 for kitchen accuracy
- fl oz → ml: multiply by 30 for a quick estimate (29.57 exact)
Worked example
Converting 10 litres to US gallons: 10 ÷ 3.785411784 = 2.642 gal. The same
10 litres is 2.20 UK gallons, 10,000 ml, or about 42.3 US cups.
Frequently asked questions
How many litres are in a US gallon?
1 US gallon = 3.785411784 litres exactly. So 10 litres ≈ 2.64 US gallons, and a 50-litre fuel tank holds about 13.2 US gallons.
Why are US and UK gallons different?
They have different historical definitions: the US gallon is 231 cubic inches (3.785 L), while the UK (imperial) gallon is exactly 4.54609 L — about 20% larger. UK pints and fluid ounces are correspondingly bigger too, which is why a UK pint of beer (568 ml) beats a US pint (473 ml).
How many ml are in a cup?
A US legal cup used in recipes is 240 ml, but the exact US customary cup is 236.588 ml (8 US fl oz) — the value this converter uses. A metric cup, common in Australia, is 250 ml.
How many cubic metres is 1,000 litres?
Exactly 1 m³ — a litre is defined as one cubic decimetre, and 1,000 of them fill a cube one metre on each side. Water utilities often bill per m³, i.e. per 1,000 L.
How many fluid ounces are in a litre?
About 33.8 US fluid ounces (1 US fl oz = 29.5735 ml). A standard 500 ml bottle is roughly 16.9 US fl oz, which is why US bottled water is labelled 16.9 oz.