Volume Converter

About this Volume Converter

The Volume Converter handles metric capacity units alongside common US customary kitchen and liquid volume units. The tool uses liters internally and converts the entered quantity to the selected destination unit.

Volume units differ not only between metric and imperial systems but also between US and UK imperial systems specifically, so converting liquid volumes correctly matters for cooking, fuel purchases, and any recipe or specification sourced from a different country.

For related tasks, try Cooking Measurement Converter, Weight Converter or Length Converter.

How to use it

1. Enter the quantity.
2. Choose the source volume unit.
3. Choose the destination unit and convert.

Practical example

One US gallon is approximately 3.78541 liters, while one liter is roughly 4.22675 US cups.

1 US gallon converts to about 3.785 liters, while 1 UK imperial gallon converts to about 4.546 liters, meaning a 5 gallon fuel container means notably different actual volumes depending on the country.

Things to double-check

A US liquid gallon (3.785 liters) is meaningfully smaller than a UK imperial gallon (4.546 liters), roughly a 20% difference, so always confirm which gallon standard a source is using before converting.

Metric and US volumes

One litre is 1,000 millilitres, about 0.2642 US gallons and about 0.22 imperial gallons. One US gallon is 3.785 litres, one US quart is 0.946 litres and one US fluid ounce is about 29.57 mL. A cubic metre equals 1,000 litres, and a cubic metre of water weighs about 1,000 kilograms. A 50 litre fuel tank holds about 13.2 US gallons.

US and imperial gallons

The imperial gallon used in the UK is about 20 percent bigger than the US gallon, 4.546 litres against 3.785. Pints differ too: a US pint is 473 mL and an imperial pint is 568 mL. When you read a recipe, a fuel figure or a drink size from a different country, check which system it uses. This is a common cause of mistakes in cooking and in comparing fuel economy.

Containers and tanks

Volume conversions are used for tanks, pools and containers. A rectangular tank of 2 m by 1 m by 1.5 m holds 3 cubic metres, or 3,000 litres. A water tank labelled 1,000 litres weighs about a tonne when full, which matters for roof loading. To work out a cylinder, multiply pi times the radius squared times the height. Convert dimensions to metres first to get cubic metres.

Liquids in daily life

Drink and medicine labels use millilitres, bottles use litres, and recipes use cups and spoons. For medicine, use the dosing device supplied rather than a kitchen spoon, because spoon sizes vary. A common 5 mL measure equals one teaspoon in dosing. When you buy paint, check the coverage per litre, and when you fill a pool, use the volume in cubic metres to calculate chemicals.

Fuel and liquids when travelling

Fuel in the United States is sold by the US gallon and in most other countries by the litre. Filling 40 litres is 10.57 US gallons, and a price of 1.20 per litre equals about 4.54 per US gallon. Remember that an imperial gallon is larger than a US gallon when you compare prices or economy figures. For liquids carried on flights, containers are limited by volume in millilitres, commonly 100 mL each. Convert before you pack, so that you stay within the limits.

Tanks, pools and bottles

Volumes make more sense with examples. A pool of 8 by 4 metres with an average depth of 1.5 metres holds 48 cubic metres, which is 48,000 litres. Filling it from a hose that delivers 20 litres a minute takes 2,400 minutes, or 40 hours. A 1.5 litre bottle holds about 50.7 US fluid ounces, and a 20 litre water cooler bottle is about 5.3 US gallons. Converting to cubic metres helps when you price water deliveries or size a tank, and converting to US units helps when you read an imported product label.

Worked examples

A 2.5 litre bottle holds about 84.5 US fluid ounces, since one litre is 33.814 ounces. A tank of 5 US gallons holds about 18.9 litres. A 750 millilitre bottle is about 25.4 US fluid ounces. A fuel quantity of 40 litres is about 8.8 imperial gallons or 10.6 US gallons. When you convert, always check whether a gallon is the US or the imperial one, since they differ by about 20 percent. The converter lists the units clearly so you can avoid that mix-up.

Calculating tank volumes

To find the volume of a cylindrical tank, multiply pi by the radius squared by the height. A tank with a radius of 0.5 metres and a height of 1.2 metres holds 3.1416 times 0.25 times 1.2, which is about 0.942 cubic metres, or 942 litres. For a rectangular tank, multiply length, width and height. Convert dimensions to metres first so that the result comes out in cubic metres, which you can then convert to litres by multiplying by 1,000. Leave some space at the top, since tanks are rarely filled to the brim.

Drinks, doses and containers

Everyday containers have standard sizes: a wine bottle is 750 millilitres, a soft drink can is 330 or 355 millilitres, and a pint is 473 millilitres in the United States and 568 in the United Kingdom. For medicine, use the measuring device that comes with the product, since a household teaspoon varies and the standard dose measure is 5 millilitres. For cooking, one tablespoon is about 15 millilitres and a cup is about 240 to 250. Converting to millilitres makes recipes and doses precise.

Engines, shipping and storage

Engine size is given as displacement in cubic centimetres or litres, so 1,500 cc is 1.5 litres. A standard 20-foot shipping container has an internal volume of about 33 cubic metres, which is useful when you estimate how much a shipment will hold. Warehouses and removal companies quote space in cubic metres or cubic feet, and one cubic metre is about 35.3 cubic feet. Converting early helps you compare quotes from suppliers who use different units.

Key terms explained

A litre is a thousand millilitres, and a cubic metre is a thousand litres. A US gallon, a quart and a pint are customary units, and the imperial versions are larger. A fluid ounce measures liquid volume. A cubic centimetre equals a millilitre. Capacity is how much a container can hold, and displacement is the volume of an engine's cylinders. A teaspoon, tablespoon and cup are common kitchen measures, and a barrel of oil is about 159 litres.

Rules of thumb and quick checks

A US gallon is about 3.79 litres and an imperial gallon about 4.55. A litre is about 1.06 US quarts or 33.8 US fluid ounces. A cubic metre holds 1,000 litres and weighs about a tonne when filled with water. To find the volume of a box, multiply length, width and height in the same unit. Check whether a gallon is the US or the imperial one before you compare fuel or drink sizes.

Quick reference and sanity checks

A few anchors help you check any volume result. One litre is 1,000 millilitres, one US gallon is about 3.785 litres, and one imperial gallon is about 4.546 litres, which is roughly 20 percent more. A US fluid ounce is about 29.57 millilitres and a US cup is about 237 millilitres, though food labels often round a cup to 240. Liquid and dry measures are not interchangeable, because a cup of flour weighs far less than a cup of honey. If a recipe or a fuel figure is from another country, check whether it uses US or imperial units before you trust the converted value.

Frequently asked questions