Volume Converter (ml, l, m³, gallons, cups, ...)
Convert a volume between metric units (milliliters through cubic meters) and US/UK units (gallons, quarts, pints, fluid ounces, cups). Both US and UK gallons are included, because they are not the same size. Everything runs in your browser.
How the conversion works
Every unit on this page is defined by how many liters it represents. The input is converted to liters, then from liters into the target unit:
result = value × (liters per source unit) ÷ (liters per target unit)
Because a liter is defined as exactly one cubic decimeter, the metric side is straightforward: 1 m³ = 1000 l, and 1 ml = 1 cm³ exactly. That last equality is genuinely useful, a recipe calling for 250 ml and a spec sheet quoting 250 cm³ describe the same volume.
US and UK gallons are different units
This trips up more people than any other volume conversion. The US and the UK both inherited the imperial system, then redefined it separately.
| Unit | US | UK (imperial) | Difference |
|---|---|---|---|
| Gallon | 3.78541 l | 4.54609 l | UK is 20.1% larger |
| Quart | 0.94635 l | 1.13652 l | UK is 20.1% larger |
| Pint | 0.47318 l | 0.56826 l | UK is 20.1% larger |
| Fluid ounce | 29.5735 ml | 28.4131 ml | US is 4.1% larger |
Notice the reversal in the last row. A UK gallon is bigger than a US gallon, but a UK fluid ounce is smaller than a US one. The reason is that the two systems divide their gallon differently: a US gallon contains 128 US fluid ounces, while a UK gallon contains 160 UK fluid ounces. So the UK gallon is larger overall but split into more, smaller parts.
This matters in practice. A US recipe asking for a pint of liquid means 473 ml, while a UK recipe means 568 ml, a difference of nearly 20% that will visibly affect the result.
Quick reference table
| From | Milliliters | Liters | US gallons | US fl oz |
|---|---|---|---|---|
| 1 ml | 1 | 0.001 | 0.000264 | 0.03381 |
| 1 l | 1000 | 1 | 0.26417 | 33.814 |
| 1 m³ | 1,000,000 | 1000 | 264.172 | 33,814 |
| 1 US cup | 236.588 | 0.23659 | 0.0625 | 8 |
| 1 US pint | 473.176 | 0.47318 | 0.125 | 16 |
| 1 US quart | 946.353 | 0.94635 | 0.25 | 32 |
| 1 US gallon | 3785.41 | 3.78541 | 1 | 128 |
| 1 UK gallon | 4546.09 | 4.54609 | 1.20095 | 153.72 |
| 1 ft³ | 28,316.8 | 28.3168 | 7.48052 | 957.51 |
Practical examples
Cooking with American recipes
US recipes measure by volume where metric recipes measure by weight, which is the deeper problem behind cup conversions. A US cup is 236.588 ml, but a cup of flour and a cup of sugar weigh very differently (roughly 120 g versus 200 g). For liquids the volume conversion is exact and reliable, for dry ingredients a kitchen scale gives far more consistent results than any conversion table.
Worth knowing: a "metric cup" of 250 ml is used in Australia and some European recipes, so it is not quite the same as a US cup either.
Fuel consumption and tank sizes
A 15-gallon US car tank holds 56.8 liters. When comparing fuel economy figures internationally, check whether "gallon" means US or UK: 30 mpg (US) is 36 mpg (UK) for the same actual consumption, purely because of the unit difference.
Aquariums, tanks, and pools
Calculate the volume of a rectangular tank by multiplying length × width × height, then convert. A tank 120 cm × 40 cm × 50 cm is 240,000 cm³, which equals 240 liters or about 63 US gallons. Remember that the usable volume is always less than the geometric volume once substrate, decoration, and the gap below the rim are accounted for.
Cubic meters for shipping and construction
Freight, concrete, and soil are quoted in cubic meters or cubic yards. 1 m³ = 1.30795 yd³, and 1 yd³ = 0.764555 m³. For concrete ordering, always round up, the cost of a slightly short delivery far exceeds the cost of a small surplus.
Frequently asked questions
Is a US gallon the same as a UK gallon?
No. A US gallon is 3.78541 liters, a UK (imperial) gallon is 4.54609 liters, about 20% larger. Always check which one a source means.
How many milliliters is a US cup?
236.588 ml. This is smaller than the 250 ml metric cup used in Australia and parts of Europe, a difference of about 5.4%.
Why is a UK fluid ounce smaller than a US one when the UK gallon is bigger?
Because the two systems divide the gallon differently. A US gallon is 128 US fluid ounces, a UK gallon is 160 UK fluid ounces. More divisions of a larger whole produce smaller parts.
Is 1 milliliter the same as 1 cubic centimeter?
Yes, exactly. A liter is defined as one cubic decimeter, which makes 1 ml = 1 cm³ by definition. Medical and engineering contexts often use "cc" for cm³, which is the same thing as a milliliter.
How many liters is a cubic meter?
Exactly 1000. Note the cubing: 1 m = 100 cm, but 1 m³ = 1,000,000 cm³, because the factor is applied three times.
How do I convert liters to US gallons in my head?
Divide by 4 and add about 5%. For 20 liters: 20 ÷ 4 = 5, plus 5% gives 5.25, and the exact answer is 5.28 gallons.
Related converters
- Length converter, for the underlying linear units
- Area converter, where the factor is squared rather than cubed
- Weight converter, for recipes that specify mass instead of volume
- All unit converters