Volume Converter
Litres, gallons, pints, cups and cubic units.
Reviewed by the Calculation Machine team · Updated 24 October 2026 · How we check our maths
Your values
ⓘ Live results
- Litres
- 18.92706
- US gallons
- 5
- Imperial gallons
- 4.16337
- US fluid ounces
- 640.001
- Cubic feet
- 0.6684
| Unit | Value |
|---|---|
| ml | 18927.05892 |
| l | 18.92706 |
| galus | 5 |
| galuk | 4.16337 |
| ptus | 40.00004 |
| floz | 640.00064 |
| cuft | 0.6684 |
Quick answer
To convert volume, go through liters: 1 US gallon = 3.785411784 L, 1 imperial (UK) gallon = 4.54609 L, 1 US fluid ounce = 29.5735 ml and 1 cubic foot = 28.3168 L. So 5 US gallons is 18.93 liters, or 4.16 imperial gallons — the two gallons are not interchangeable.
What the Volume Converter does
Enter a volume in milliliters, liters, US gallons, imperial gallons, US pints, US fluid ounces or cubic feet and the converter shows it in the other units at once. It is built for practical jobs: sizing a fish tank or water butt, comparing fuel economy figures between the US and UK, scaling a homebrew recipe, or reading a bottle label in a different system.
The biggest source of error is the gallon. A US gallon is about 17% smaller than an imperial gallon, and US pints and fluid ounces are different from their UK namesakes too. This converter's pints and fluid ounces are US measures; the UK equivalents are listed in the table below.
To work out the volume of a tank or container from its dimensions first, use the cylinder and shape volume calculator, then bring the result here to change units.
The formula
value in target unit = value × (liters per source unit) ÷ (liters per target unit)
| Symbol | Meaning | Unit |
|---|---|---|
| 1 US gallon | 231 cubic inches, exact by definition | 3.785411784 L |
| 1 imperial gallon | UK and Commonwealth gallon, exact by definition | 4.54609 L |
| 1 US pint | One-eighth of a US gallon (16 US fl oz) | 473.176 ml |
| 1 US fl oz | One-128th of a US gallon | 29.5735 ml |
| 1 ft³ | Cubic foot (12 × 12 × 12 inches) | 28.3168 L |
Factors follow NIST Handbook 44 (US customary units) and the UK Weights and Measures Act 1985 (imperial gallon). The liter is exactly one cubic decimeter (1,000 cm³), so 1 ml = 1 cm³. Results for fluid ounces can show a tiny rounding tail (for example 640.001 instead of exactly 640 for 5 US gallons); round to two decimals for any practical use.
Worked examples
Soda bottle in fluid ounces
A 2-liter bottle of soda, converted for a US nutrition comparison.
Inputs
- Volume2
- FromLitres
Result
- Litres2
- US gallons0.52834
- Imperial gallons0.43994
- US fluid ounces67.628
- Cubic feet0.07063
2 liters is 67.6 US fluid ounces or 0.53 US gallons — just over half a gallon. That is about 5.6 standard 12 oz cans.
UK fuel tank in US gallons
A British classic car's manual lists a 10-gallon tank, which means imperial gallons.
Inputs
- Volume10
- FromImperial gallons
Result
- Litres45.4609
- US gallons12.0095
- Imperial gallons10
- US fluid ounces1537.217
- Cubic feet1.60544
10 imperial gallons is 45.46 liters or 12.01 US gallons. Fuel economy follows the same ratio: a car doing 40 mpg (UK) does about 33 mpg (US).
Cubic feet for an aquarium or raised bed
A tank or planter holds 1 cubic foot and you need it in gallons and liters.
Inputs
- Volume1
- FromCubic feet
Result
- Litres28.3168
- US gallons7.48051
- Imperial gallons6.22883
- US fluid ounces957.506
- Cubic feet1
1 cubic foot is 7.48 US gallons or 28.3 liters. Multiply by your cubic-foot total to size water treatments or bags of soil sold by the liter.
US vs imperial (UK) liquid measures
Same names, different sizes. The imperial pint has 20 fluid ounces against the US pint's 16, but the imperial fluid ounce is slightly smaller, so the pints still differ by about 20%.
| Unit | US | Imperial (UK) | UK ÷ US |
|---|---|---|---|
| Gallon | 3,785.41 ml | 4,546.09 ml | 1.201 |
| Quart | 946.35 ml | 1,136.52 ml | 1.201 |
| Pint | 473.18 ml | 568.26 ml | 1.201 |
| Fluid ounce | 29.57 ml | 28.41 ml | 0.961 |
Kitchen and container sizes
- US cup: 8 US fl oz, about 236.6 ml. US nutrition labels use a rounded 240 ml cup, while Australia, Canada and New Zealand use a 250 ml metric cup.
- Tablespoon and teaspoon: a US tablespoon is about 14.8 ml and a teaspoon about 4.9 ml; metric spoons are 15 ml and 5 ml. For recipe work, the cooking measurement converter handles cups, spoons and ingredient weights.
- Wine bottle: 750 ml, about 25.4 US fl oz.
- Beer: a US pint glass holds 16 US fl oz (473 ml); a British pint is 568 ml.
- Water by weight: 1 liter of water has a mass of about 1 kg, and 1 US gallon about 8.34 lb — use the weight converter to go further.
Cubic units and liquid units
Engineers and builders often measure space in cubic units, while liquids are sold in liters or gallons. The links are fixed: 1 cubic foot holds 7.48 US gallons, 1 cubic inch is 16.387 ml, and 1 cubic meter is 1,000 liters (about 264.2 US gallons or 35.3 cubic feet). One cubic yard, the unit for concrete and topsoil, is 27 cubic feet or about 764.6 liters.
How to use the Volume Converter
- 1Enter the volume as a number.
- 2Choose its unit. Check whether a gallon figure is US or imperial — UK, older Canadian and some Caribbean sources use imperial.
- 3Read every equivalent. Pints and fluid ounces shown are US measures.
- 4For UK pints or imperial fluid ounces, convert to milliliters here and divide by 568.26 or 28.41.
Frequently asked questions
How many liters are in a gallon?
A US gallon is 3.785 liters and an imperial (UK) gallon is 4.546 liters. If the source is American, use 3.785.
How many ounces are in a liter?
One liter is 33.81 US fluid ounces, or 35.2 imperial fluid ounces.
How many cups are in a liter?
About 4.23 US cups of 236.6 ml, or exactly 4 metric cups of 250 ml.
How many gallons are in a cubic foot?
One cubic foot holds 7.48 US gallons or 6.23 imperial gallons, which is 28.3 liters.
Why are US and UK gallons different?
The US kept the older 231-cubic-inch wine gallon, while Britain defined the imperial gallon in 1824 as the volume of 10 pounds of water. The imperial gallon is about 20% larger.
References
- NIST Handbook 44, Specifications, Tolerances, and Other Technical Requirements for Weighing and Measuring Devices (Appendix C, General Tables of Units of Measurement) — National Institute of Standards and Technology
- Weights and Measures Act 1985 — UK Parliament (legislation.gov.uk)
About this calculator
- Built and reviewed by the Calculation Machine team · How we build and test calculators
- Last reviewed: October 24, 2026
- Report an error