What this calculator does
Volume conversion has more units in everyday use than almost any other measure, because cooking, fuel, plumbing and shipping each settled on their own: millilitres and litres in the metric world, but cups, pints, quarts, gallons and fluid ounces all coexisting in the US kitchen alone.
Every one of them converts through the litre as a base, so a figure in US cups reaches imperial gallons the same way it reaches millilitres: one multiplication into litres, one division back out.
The formula
The tricky part of volume conversion is not the arithmetic but which gallon or cup is meant. This calculator uses the US customary units throughout except where the imperial gallon is explicitly listed, and the US gallon (3.78541 L) is about 17 per cent smaller than the imperial gallon (4.54609 L): a difference that matters for fuel economy and recipe conversions between US and UK sources.
| Term | Meaning |
|---|---|
| Base unit | The litre, which every other unit converts through. |
| US gallon | 3.78541 litres: used in the US for fuel and most liquid measure. |
| Imperial gallon | 4.54609 litres: used in the UK and historically across the Commonwealth, about 20 per cent larger than the US gallon. |
The inputs explained
| Field | What to enter |
|---|---|
| Value | The value to convert. |
| From | The unit you are converting from. |
| To | The unit you want the answer in. |
When to use it
Converting a recipe between US and metric measures
US cups, tablespoons and teaspoons are volume measures that convert to millilitres here, letting a US recipe be followed with a metric measuring jug or the reverse.
Checking fuel economy or tank capacity across US and UK figures
A US gallon and an imperial gallon are different sizes, so a fuel figure quoted in one needs an explicit conversion, not just a unit-name swap, before it means anything in the other.
Sizing a tank, container or pool in litres
Cubic metres convert directly to litres at a factor of exactly 1,000, useful for translating a container’s dimensions-based volume into a familiar capacity figure.
Working with laboratory or medical dosing volumes
Millilitres and fluid ounces both appear on medicine labels depending on the market: this handles the conversion at the same precision as the rest of the ladder.
Worked examples
Every figure in the tables below is produced by this page’s own calculator at build time, so the numbers and the tool always agree. Select any row to load that scenario.
One of each unit, converted to litres
A single unit of volume from millilitres to imperial gallons, each converted to litres to compare true scale.
| From | In litres |
|---|---|
| Millilitre | 0.001 L |
| Teaspoon (US) | 0.00492892 L |
| Tablespoon (US) | 0.0147868 L |
| Cup (US) | 0.236588 L |
| Pint (US) | 0.473176 L |
| Quart (US) | 0.946353 L |
| Gallon (US) | 3.78541 L |
| Gallon (imperial) | 4.54609 L |
Converting 2 litres to other units
A 2-litre bottle, a common reference size, expressed in each of the other units.
| To | Result |
|---|---|
| Millilitres | 2,000 ml |
| Cups (US) | 8.45351413 cup |
| Pints (US) | 4.22675706 pt |
| Quarts (US) | 2.1133763 qt |
| Gallons (US) | 0.52834435 gal |
Questions
Is a US gallon the same as an imperial gallon?
No: a US gallon is 3.78541 litres and an imperial gallon is 4.54609 litres, about 20 per cent larger. Always check which one a figure refers to before comparing fuel economy or container sizes across US and UK sources.
How many millilitres are in a US cup?
About 236.6 ml. A metric cup, used in Australia and some other countries, is a rounder 250 ml instead: a third, separate definition worth checking in a recipe’s country of origin.
How do I convert cubic metres to litres?
Multiply by 1,000: a cubic metre is defined as exactly 1,000 litres, since a litre is in turn defined as a cube 10 cm on each side.
What is the difference between a US tablespoon and an Australian tablespoon?
A US tablespoon is about 14.8 ml; an Australian tablespoon is 20 ml, noticeably larger. This calculator uses the US tablespoon: for Australian cooking measures specifically, see the cooking measures converter.
How many fluid ounces are in a US pint?
16 fluid ounces make a US pint. A UK imperial pint is a different, larger unit again (about 568 ml versus the US pint’s 473 ml), which is why a "pint" of beer differs between the two countries.
For kitchen-specific units like Australian tablespoons and metric cups, see the cooking measures converter. For mass rather than volume, use the weight and mass converter.