🧪 Volume

Volume Converter

Cooking, fuel, aquariums or shipping containers — convert liters, cubic metres, US gallons, imperial gallons, cups and fluid ounces. Press Convert to get your answer.

Written and reviewed by SM Arijul Islam · Last reviewed 28 October 2026 · Editorial standards · Report an error

About the volume converter

Volume units differ between countries more than almost any other measurement. A US gallon is about 3.785 litres while an imperial gallon is about 4.546 litres — a 20% difference that can ruin a recipe or a fuel-cost calculation. Always double-check which gallon you have, and this converter will do the rest.

Exact and customary factors

1 litre = 1,000 millilitres = 1,000 cm³
1 m³ = 1,000 litres
1 US gallon = 3.785411784 L · 1 imperial gallon = 4.54609 L
1 US cup = 8 US fluid ounces = 236.588 mL
1 oil barrel = 158.987 L

For kitchen-specific measures such as metric cups, tablespoons and dry ingredient weights, use the Cooking Converter.

How to convert volume

Volume measures three-dimensional space, with the litre and cubic metre as the metric staples and the US and UK gallon systems running alongside them. The two gallons are not the same: a US gallon is 3.785411784 L while a UK (imperial) gallon is 4.54609 L. Fluid ounces, cups, pints and quarts all follow whichever system they belong to, which is why recipes need care.

Common volume conversions

One liter expressed in other units of volume
Unit	1 liter equals
Milliliter (mL)	1,000
US fluid ounce (fl oz)	33.814023
US cup (cup)	4.2267528
US quart (qt)	1.0566882
US gallon (gal)	0.26417205
Imperial gallon (imp gal)	0.21996925
Cubic foot (ft³)	0.035314667
Cubic meter (m³)	0.001

Everyday uses

Cooking, baking and recipe scaling
Fuel, tank and container capacity
Shipping, freight and storage planning
Mixing paint, chemicals or concrete
Drinks, brewing and bottling

Frequently asked questions

How many millilitres are in a litre?

1,000. A cubic metre is 1,000 litres, and a millilitre is identical in size to a cubic centimetre.

Is a US fluid ounce the same as a UK one?

No. A US fluid ounce is 29.5735295625 mL, while a UK fluid ounce is 28.4130625 mL.

How many litres are in a US gallon?

3.785411784 L, against 4.54609 L for a UK (imperial) gallon.

How many millilitres is a teaspoon?

About 4.92892159375 mL in the US system, or exactly 5 mL for a metric teaspoon.

More worked examples

One US gallon is 3.785412 litres.
One US cup is 236.588 mL, while a metric cup is 250 mL.
Two litres of water has a mass of two kilograms, because water has a density of about 1 kg per litre.
One US fluid ounce is 29.5735 mL, and one UK fluid ounce is 28.4131 mL.

Quick reference

Common exact volume conversion factors
Conversion	Exact value
1 US gallon	3.785412 L
1 UK gallon	4.546092 L
1 litre	0.264172 US gal
1 US quart	0.946353 L
1 US pint	0.473176 L
1 US cup	236.588 mL
1 US fluid ounce	29.5735 mL
1 cubic metre	1,000 L

Common mistakes to avoid

Using a US gallon when a recipe or fuel figure means a UK one. The imperial gallon is 4.546 litres against 3.785, a difference of about 20 percent.
Treating fluid ounces as weight ounces. One fluid ounce of water weighs a little over one ounce, but the two diverge for almost every other liquid.
Assuming a cup is 250 mL everywhere. That is the metric cup, and the US cup is smaller.
Forgetting that cubic centimetres and millilitres are interchangeable in practice, so no conversion is needed between them.

Further questions

How many millilitres are in a US cup?

236.588 mL, which is also 8 US fluid ounces.

Why is a UK pint larger than a US pint?

Because the imperial gallon is defined as 4.546 litres while the US gallon is 3.785 litres, and both are divided into eight pints.

How many litres are in a cubic metre?

Exactly 1,000. A cubic metre is 100 cm on each side, which is one million cubic centimetres, and each is one millilitre.

Is one millilitre exactly one cubic centimetre?

Yes, since 1964 the litre has been defined as exactly one cubic decimetre, so a millilitre is exactly a cubic centimetre.

Sources and standards

The cubic metre is the SI unit of volume. The US gallon is exactly 231 cubic inches, or 3.785411784 L, while the imperial gallon is 4.54609 L; those definitions, not rounded kitchen figures, are what this converter applies.