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Convert litres, cubic metres, US and imperial gallons, pints, cups and spoons — every unit labelled by country, because a gallon and a pint mean different volumes depending on who is asking.
Two countries kept the same words for different volumes, and the gap is large enough to matter.
| Unit | US | Imperial (UK/AU) | Difference |
|---|---|---|---|
| Gallon | 3.785 L | 4.546 L | Imperial 20% bigger |
| Quart | 946 mL | 1,137 mL | Imperial 20% bigger |
| Pint | 473 mL | 568 mL | Imperial 20% bigger |
| Fluid ounce | 29.57 mL | 28.41 mL | US 4% bigger |
Australia uses imperial-derived units where any survive — a pint of beer here is the 568 mL one — but everything official is metric. American recipes, American car reviews and American product specifications all use the smaller gallon and the larger ounce.
The pint is where this becomes tangible. An Australian or British pint is 568 mL; an American pint is 473 mL — nearly 100 mL less for the same word.
The measure that ruins the most recipes is not the gallon — it is the tablespoon.
| Measure | Australia | US | UK |
|---|---|---|---|
| Tablespoon | 20 mL | 14.79 mL | 15 mL |
| Teaspoon | 5 mL | 4.93 mL | 5 mL |
| Cup | 250 mL | 237 mL | 250 mL |
One more trap worth naming: an American recipe measuring flour in cups is measuring volume, not weight, and how tightly the flour is packed changes the result substantially. Where accuracy matters, weigh it — the weight converter handles grams and ounces.
The metric side has no ambiguity at all, because the units are defined from each other.
A millilitre is a cubic centimetre — the same volume with two names, which is why medical and scientific writing uses cc and mL interchangeably. And a litre is exactly one cubic decimetre, which has been its definition since 1964.
| Unit | In litres | Typically used for |
|---|---|---|
| Millilitre (mL) | 0.001 | Medicine, cooking, small containers |
| Cubic centimetre (cm³) | 0.001 | Engine capacity, scientific work |
| Litre (L) | 1 | Drinks, fuel, everyday capacity |
| Cubic metre (m³) | 1,000 | Concrete, soil, water tanks, freight |
| Cubic inch (in³) | 0.0164 | American engine sizes |
| Cubic foot (ft³) | 28.32 | Shipping volume, gas, refrigerators |
Often used interchangeably, and the distinction is occasionally useful.
| Volume | Capacity | |
|---|---|---|
| Describes | The space an object occupies | How much a container holds |
| Applies to | Solids, liquids, gases | Containers |
| Usual units | m³, cm³ | L, mL |
| Example | A brick has a volume of 1,900 cm³ | A bottle has a capacity of 1.25 L |
Cubic metres are the working unit for anything delivered by the truckload, and volume is what you order even though mass is what arrives.
| Material | 1 m³ weighs about |
|---|---|
| Concrete | 2.4 tonnes |
| Sand (dry) | 1.6 tonnes |
| Gravel | 1.7 tonnes |
| Topsoil | 1.3 tonnes |
| Mulch | 0.4 tonnes |
| Water | 1 tonne |
A 5 × 4 m slab at 100 mm thick is 2 m³ of concrete, which is about 4.8 tonnes. Ordering is done in cubic metres; the truck's limits are in tonnes. Our mass calculator converts between the two, and the density calculator handles any material not listed.
How do you convert litres to gallons?
It depends which gallon. Divide litres by 3.785412 for US gallons, or by 4.54609 for imperial gallons — a 20% difference. Australia and the UK use the imperial gallon where the unit survives at all, while American sources always mean the smaller US gallon.
What is the difference between a US and an imperial gallon?
An imperial gallon is 4.54609 litres and a US gallon is 3.785412 litres, so the imperial one is about 20% larger. This makes fuel economy figures in miles per gallon meaningless without knowing which gallon is meant — the same car looks more efficient quoted in imperial mpg.
Why is a US fluid ounce bigger than an imperial one?
Because the two systems divide their gallons differently. A US gallon contains 128 US fluid ounces while an imperial gallon contains 160 imperial fluid ounces — more, smaller ounces in a larger gallon. So the US fluid ounce is 29.57 mL against the imperial 28.41 mL, even though the US gallon is the smaller of the two.
How many millilitres are in a litre?
Exactly 1,000. The metric relationships are all definitional: 1,000 mL is 1 L, 1,000 L is 1 m³, and 1 mL is exactly 1 cm³. Nothing is approximated on the metric side.
Is a millilitre the same as a cubic centimetre?
Yes, exactly the same volume. A litre is defined as one cubic decimetre, which makes a millilitre precisely one cubic centimetre. This is why medical and scientific writing uses cc and mL interchangeably, and why engine capacities appear in both.
How many litres are in a cubic metre?
Exactly 1,000. A cubic metre is the working unit for concrete, soil, mulch and freight, while litres are used for liquids — but a 5,000 L water tank and a 5 m³ water tank are the same tank.
How many mL is an Australian tablespoon?
Twenty millilitres — four teaspoons. Australia rounded to 20 mL at metrication while the UK settled on 15 mL and the US uses about 14.79 mL. Three Australian tablespoons is 60 mL against roughly 44 mL for three American ones, which is enough to change how a recipe behaves.
How many cups are in a litre?
Four Australian metric cups, since each is 250 mL. Using American cups at 237 mL you would need about 4.2. The difference is around 5% per cup, which is tolerable in cooking but shows up in baking where ratios matter.
What is the SI unit of volume?
The cubic metre. The litre is not strictly an SI unit but is accepted for use with SI, and is defined as exactly one cubic decimetre — one thousandth of a cubic metre.
How do I convert cubic feet to cubic metres?
Multiply by 0.0283168. The factor is the length conversion cubed: a foot is 0.3048 m, and 0.3048³ gives 0.0283168. Forgetting to cube the factor is a common error that produces an answer roughly 35 times too large.
What is the difference between volume and capacity?
Volume is the space something occupies; capacity is how much a container can hold. In practice the units are interchangeable — litres and cubic metres measure both — and the distinction is more about which word fits the sentence than any difference in the quantity.
Is a fluid ounce the same as an ounce?
No. A fluid ounce measures volume and an ounce measures mass. They are only numerically close for water, by historical coincidence rather than design. A fluid ounce of honey and a fluid ounce of oil have quite different masses.
Metric volume is unambiguous — millilitres, litres and cubic metres are defined from each other with nothing approximated. Everything else needs a nationality before it means anything.
A gallon, a pint, a fluid ounce, a tablespoon and a cup all describe different volumes depending on where the source came from, and the differences run from 5% to 20%. The converter above labels every one of them for exactly that reason.
For the other measurement types, the unit converter covers ten categories, and the mass calculator turns a volume of material into a mass.