Converters

Volume Converter

Convert any volume instantly: litres, millilitres, cubic metres, US and UK gallons, cups and fluid ounces – accurate and both ways.

✓ Reviewed by Julian Bronski · updated June 2026

How do you convert volume between litres, millilitres and gallons?

Convert through the base unit litre: 1 litre is 1000 ml, 1000 litres make a cubic metre. For gallons multiply by 3.785 (US) or 4.546 (UK). Example: 2 litres divided by 3.785 is about 0.53 US gallons. That keeps every conversion exact and traceable.

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How does the Volume Converter work?

Each unit is first converted into the base litre via its factor, then divided into the target unit: target = value × factorfrom ÷ factorto. Example: 1 US gallon × 3.785411784 = 3.785 litres, which is 3785 ml. Note: the US gallon (3.785 L) is smaller than the UK gallon (4.546 L) – never copy recipes or fuel figures blindly.

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How to read the result

The converter shows you the same volume in a different unit – the amount of liquid stays physically identical, only the scale changes. A small number with a large unit (0.5 cubic metres) can be the very same amount as a large number with a small unit (500 litres). So always look at the unit behind the number, not just the digit itself.

What orders of magnitude are typical in daily life?

With anchors like these you can instantly judge whether a conversion result is plausible. If a cup of coffee suddenly comes out as "2 litres", you most likely mistyped the starting unit.

Common mistakes

The classic error is confusing weight and volume. One litre of water weighs almost exactly 1 kilogram, but one litre of honey weighs about 1.4 kg and one litre of oil only around 0.9 kg. Anyone copying a recipe from grams to millilitres "one to one" will be off for dense or light ingredients. A second pitfall is US recipes: cup, tablespoon and teaspoon are volume measures, not weight measures – and the US cup (236.6 ml) is not the metric cup (250 ml).

Practical tips

When cooking it pays to convert every ingredient into a single unit up front, instead of constantly jumping between ml, cups and spoons inside the recipe. For garden and pool, think in litres and cubic metres: 1 m³ holds exactly 1000 litres, which makes dosing fertiliser or chlorine simple. And with international fuel figures, always check whether US or UK gallons are meant – the roughly 20 % difference decides whether your range calculation holds up.

When a plain conversion is not enough

Volume depends on temperature: warm water expands, cold water contracts. For everyday and kitchen use this is negligible, but in a lab, in chemistry, or when filling fuel precisely it can matter. With bulk goods like flour or rice, a volume measure only captures the space taken up, not the exact mass – loosely filled flour weighs less than firmly packed flour. For precise dosing in such cases, a scale is the more honest choice.

Frequently asked questions

How many ml are in a litre?
Exactly 1000 ml make 1 litre. One cubic metre (m³) equals 1000 litres, or one million millilitres.
US gallon or UK gallon?
A US gallon is 3.785 litres, while the UK (imperial) gallon is 4.546 litres – about 20 % more. The US uses the US gallon; the UK historically uses the imperial gallon.
How big is a US cup?
A US cup holds 8 US fluid ounces, roughly 236.6 ml. Watch out: the metric cup of 250 ml is slightly larger.
How many tablespoons make 100 ml?
One tablespoon holds about 15 ml, one teaspoon about 5 ml. So 100 ml is roughly 6.7 tablespoons or 20 teaspoons. These are approximations, because spoons vary slightly in size depending on the country and the set.
How much volume does a cubic metre of water hold in litres?
Exactly 1000 litres. A cubic metre is a cube one metre on each side. That is handy for a pool, water butt or aquarium: multiply length × width × height in metres and you get the volume directly in cubic metres, i.e. in thousand-litre steps.
Does a volume measure convert grams correctly on its own?
No. Volume and weight are linked by density, which differs from substance to substance. Only for water does roughly 1 ml = 1 g hold. For flour, oil, honey or sugar you need the specific density or a kitchen scale, otherwise the amount will be wrong.

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