# Volume Converter - Litres, Millilitres, Cups, Pints, Quarts and Gallons (US and Imperial)

Page: https://hirantha.me/tools/volume-converter
Part of: Hirantha Sandaruwan Lakshan free tools (https://hirantha.me/tools)
Updated: 2026-10-13

Convert millilitres, litres, cubic metres, US teaspoons, cups, pints, quarts, gallons and imperial units exactly, with US and UK kept clearly apart.

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Convert volume between millilitres, litres, cubic metres, the US measures (teaspoon, tablespoon, fluid ounce, cup, pint, quart, gallon) and the imperial measures used in the UK, with the two systems listed under separate headings. A US gallon is exactly 3.785411784 L and an imperial gallon is exactly 4.54609 L, so the same word can mean amounts about 20 percent apart.

Every volume is held as an exact fraction of a cubic metre. A cubic unit uses the cube of its length factor, so 1 cubic inch is exactly 0.0254 x 0.0254 x 0.0254 m³, which is 16.387064 mL. Conversions use whole numbers rather than floating point, so a conversion followed by its reverse returns the number you typed. The answer is rounded only when it is shown: Auto shows an exact result in full when it fits in 14 digits and otherwise rounds to 10 significant digits.

The US liquid units all come from the gallon, which is defined as 231 cubic inches, exactly 3.785411784 L. A quart is 1/4 gallon (946.352946 mL), a pint is 1/8 (473.176473 mL), a cup is 1/16 or 8 fluid ounces (236.5882365 mL) and a fluid ounce is 1/128 (29.5735295625 mL). A tablespoon is half a fluid ounce and a teaspoon is a third of a tablespoon. NIST Handbook 44 lists these relations.

The imperial gallon is exactly 4.54609 L in the UK Weights and Measures Act 1985, and NIST SP 811 gives the same figure. An imperial quart is 1/4 of it, a pint is 1/8 (568.26125 mL) and a fluid ounce is 1/160 (28.4130625 mL). So an imperial pint holds 20 fluid ounces and a US pint holds 16. NIST describes the imperial gallon as about 20 percent larger than the US gallon, and the exact ratio is 1.200949926. An imperial fluid ounce is slightly smaller than a US one.

A litre is one cubic decimetre, so 1 L is 1,000 cm³ and 1 mL is 1 cm³. This converter uses the US customary cup and spoons. NIST calls the cup, tablespoon and teaspoon measuring units and rounds them to 237, 15 and 5 mL. Recipes in Australia, Canada and New Zealand use a 250 mL metric cup, and US nutrition labels define a cup as 240 mL, so check which one a recipe means. For baking, weighing the ingredients is more reliable than measuring by volume.

US and imperial (UK) units side by side, in millilitres:
| Unit | US (mL) | Imperial (mL) | Imperial divided by US |
| --- | --- | --- | --- |
| Fluid ounce | 29.5735295625 | 28.4130625 | 0.9607599404 |
| Pint | 473.176473 | 568.26125 | 1.200949926 |
| Quart | 946.352946 | 1,136.5225 | 1.200949926 |
| Gallon | 3,785.411784 | 4,546.09 | 1.200949926 |

Q: How many litres are in a US gallon?
A: Exactly 3.785411784 L. A US gallon is defined as 231 cubic inches, and a cubic inch is exactly 16.387064 mL.

Q: How many litres are in an imperial gallon?
A: Exactly 4.54609 L, as defined in the UK Weights and Measures Act 1985. That is about 20 percent more than a US gallon, so 1 imperial gallon is 1.200949926 US gallons.

Q: What is the difference between a US pint and an imperial pint?
A: A US pint is 16 US fluid ounces, 473.176473 mL. An imperial (UK) pint is 20 imperial fluid ounces, 568.26125 mL. The imperial pint is about 20 percent bigger, even though its fluid ounce is slightly smaller.

Q: How many millilitres are in a cup?
A: A US customary cup is 236.5882365 mL. Cups in other places differ: a 250 mL metric cup is used in Australia, Canada and New Zealand, and US nutrition labels use 240 mL. Pick the cup your recipe uses.

Q: How many millilitres are in a teaspoon and a tablespoon?
A: A US teaspoon is 4.92892159375 mL and a US tablespoon is 14.78676478125 mL. NIST rounds them to 5 and 15 mL, and most recipes use those round numbers.

Q: Is 1 mL the same as 1 cm³?
A: Yes. A litre is one cubic decimetre, which is 1,000 cm³, so 1 mL is exactly 1 cm³. A cubic metre is 1,000 L.

Q: Why do other converters give a different answer?
A: Usually because they use a different gallon, pint or cup. Check whether a US, imperial or metric unit is meant, and whether the other site rounds early. This page keeps the units apart and shows the exact value when it fits in 14 digits.

Sources: NIST Handbook 44 (2026 edition), Appendix C, General Tables of Units of Measurement (exact inch, foot, yard, mile, rod, chain, furlong, square perch, acre, cup, tablespoon, teaspoon, US gallon, pound, carat, troy ounce, nautical mile), checked 2026-10-13 (https://www.nist.gov/document/2026-nist-handbook-44-appendix-c-word); NIST Special Publication 811 (2008), Appendix B.8, factors for units listed alphabetically (exact foot, inch, yard, mile, nautical mile, carat, grain, hectare, imperial gallon and the temperature formulas), checked 2026-10-13 (https://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors/nist-guide-si-appendix-b8); Weights and Measures Act 1985, Schedule 1 (yard, mile, acre, rood, stone, pound, imperial gallon and fluid ounce definitions, as revised and current on 5 October 2026; the page flags that Schedule 1 is due to be omitted by the Product Regulation and Metrology Act 2025 from a day to be appointed, so the page may change), legislation.gov.uk, checked 2026-10-13 (https://www.legislation.gov.uk/ukpga/1985/72/schedule/1); Wikipedia, Cup (unit) (secondary source for the 250 mL metric cup and the 240 mL US nutrition labelling cup), checked 2026-10-13 (https://en.wikipedia.org/wiki/Cup_(unit))

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