Volume Converter

About the Volume Converter

Volume is where unit conversion gets tricky. Not only do metric and imperial systems differ, but the United States and Britain use gallons, pints and fluid ounces of different sizes, and cooking adds cups, tablespoons and teaspoons. A fuel economy figure, a recipe, a paint tin, a drinks label or a fish tank's capacity can all mislead if the wrong gallon or cup is assumed.

This volume converter converts between fifteen units of volume: millilitres, litres and cubic metres; US teaspoons, tablespoons, fluid ounces, cups, pints, quarts and gallons; UK fluid ounces, pints and gallons; and cubic inches and cubic feet. It gives the result, the exact factor both ways, the value in every other unit, and the amount in both US and UK gallons.

How to Use the Volume Converter

Enter the value to convert.

Choose the unit to convert from and to. US and UK units are listed separately, so pick the one your source uses.

The converted volume appears with the factor, the value in every unit, and a US and UK gallon comparison.

How Volume Conversion Works

Every unit is converted through litres, using exact definitions:

Step-by-Step Example

2 litres to US gallons.

  2 ÷ 3.785411784 = 0.528344 US gal

So a 2-litre bottle holds about 0.528344 US gallons. The same volume is about 0.439938 UK gallons, 8.45351 US cups and 67.628 US fluid ounces.

1 UK pint to US pints.

  0.56826125 L ÷ 0.473176473 L = 1.20095 US pt

A British pint of milk or beer is about 20 percent larger than an American one.

Quick Reference

  1 L       = 0.264172 US gal = 0.219969 UK gal
  1 L       = 4.22675 US cups = 33.814 US fl oz
  1 US gal  = 3.78541 L       1 UK gal = 4.54609 L
  1 US cup  = 236.588 ml      1 US fl oz = 29.5735 ml
  1 UK pint = 568.261 ml      1 US pint = 473.176 ml
  1 US tbsp = 14.7868 ml      1 US tsp  = 4.92892 ml

US and UK Units

Britain redefined its gallon in 1824 as the volume of 10 pounds of water, while the United States kept an older wine gallon of 231 cubic inches. The result is that every US liquid measure built on the gallon is smaller than its British namesake: the US gallon, quart and pint are all about 17 percent smaller than the UK ones. The fluid ounce goes the other way — the US fluid ounce is about 4 percent larger — because the US pint is divided into 16 fluid ounces and the UK pint into 20.

This matters for fuel economy (miles per UK gallon figures look better than miles per US gallon), for older British recipes, and for drinks, where a "pint" in a British pub and an American bar are different sizes.

Cooking Measures

Kitchen spoons and cups are volume measures. A US cup is 236.588 ml, but the US nutrition label cup is a rounded 240 ml, and the metric cup used in Australia, New Zealand and Canada is 250 ml. A US tablespoon is 14.7868 ml; an Australian tablespoon is 20 ml. For baking, where accuracy matters, weighing ingredients is more reliable than converting cups, because a cup of flour can vary by 20 percent depending on how it is packed.

Cubic Units and Containers

Litres and cubic metres are linked directly: a cubic metre holds 1,000 litres and a litre is a cube 10 cm on each side. That makes it easy to find the capacity of a tank, pond or room: multiply length × width × depth in metres to get cubic metres, then multiply by 1,000 for litres. In US units, a cubic foot holds about 7.48052 US gallons, which is how aquarium and pool capacities are usually worked out.

Volume and Weight of Water

The metric system was designed so that volume and weight line up for water: a litre of water weighs very nearly one kilogram, and a millilitre about one gram. That makes quick estimates easy — a 200-litre water butt holds about 200 kg of water when full, and a 1.5-litre bottle weighs about 1.5 kg. The old British gallon was defined in a similar spirit, as 10 pounds of water, so a UK pint of water weighs about 1.25 pounds. The relationship holds only for water; milk is slightly heavier, oil lighter, and honey about 40 percent heavier by volume.

Drinks and Labels

Drinks labels in most countries show millilitres or centilitres, where a centilitre is 10 millilitres: a 75 cl wine bottle holds 750 ml, about 25.4 US fluid ounces. A standard US can of 12 fluid ounces holds 355 ml, while a common European can holds 330 ml.

Understanding Your Result

The headline is the converted volume.

The conversion factor shows the factor in both directions.

The in every unit line lists the volume in all fifteen units.

The also line compares US and UK gallons for the same amount.

When Should You Use This Calculator?

Use it for recipes written in cups, fluid ounces or millilitres.

Use it for fuel, paint, garden chemicals and cleaning products sold in litres or gallons.

Use it to work out the capacity of tanks, ponds, aquariums and pools.

Use it when reading labels or prices from another country.

Common Mistakes

Assuming all gallons are the same. The UK gallon is about 20 percent larger than the US gallon.

Mixing fluid ounces and ounces. Fluid ounces measure volume; ounces measure weight.

Using cups for baking by weight. A cup of flour and a cup of sugar weigh different amounts.

Using a metric cup for a US recipe. 250 ml is about 6 percent more than a US cup.

Forgetting cubic units cube the factor. A cubic foot is 0.3048³ cubic metres.