Volume converter — litres, gallons, cups and cubic metres

Eighteen volume units, from a teaspoon to an oil barrel, because volume is where American, British and metric measures collide most often — and where the same word means two different sizes.

How to use it

  1. 1

    Type into any row — say l or US gal. The results appear immediately, no button needed.

  2. 2

    Need a combined figure? Fill in two rows, for example l and ft³, and they are added together before converting.

  3. 3

    Set how many digits you want (4–12) and click a result to copy the plain number.

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Exact conversion factors

These are the definitions the calculator uses. Nothing here is rounded for convenience — where a value is exact by definition, it says so.

  • 1 US gallon = 3.785411784 l exactly · 1 imperial gallon = 4.54609 l exactly
  • 1 l = 0.264172052 US gal = 0.219969157 UK gal
  • 1 ft³ = 28.316846592 l · 1 in³ = 16.387064 ml
  • 1 US cup = 236.5882365 ml · 1 tbsp = 14.7867648 ml · 1 tsp = 4.92892159 ml
  • 1 oil barrel = 158.987294928 l = 42 US gallons
Formulal = US gal × 3.785411784 · l = UK gal × 4.54609 · l = ft³ × 28.316846592 · ml = US cup × 236.5882365

Volume conversion table — every unit

One of each unit, converted into the three units people ask for most.

UnitlUS galft³
1 m³1 000 l264.172 US gal35.3147 ft³
1 l1 l0.264172 US gal0.0353147 ft³
1 ml0.001 l0.000264172 US gal0.0000353147 ft³
1 cm³0.001 l0.000264172 US gal0.0000353147 ft³
1 mm³0.000001 l0.000000264172 US gal0.0000000353147 ft³
1 yd³764.555 l201.974 US gal27 ft³
1 ft³28.3168 l7.48052 US gal1 ft³
1 in³0.0163871 l0.004329 US gal0.000578704 ft³
1 bbl158.987 l42 US gal5.61458 ft³
1 US gal3.78541 l1 US gal0.133681 ft³
1 US qt0.946353 l0.25 US gal0.0334201 ft³
1 US pt0.473176 l0.125 US gal0.0167101 ft³
1 US cup0.236588 l0.0625 US gal0.00835503 ft³
1 US fl oz0.0295735 l0.0078125 US gal0.00104438 ft³
1 UK gal4.54609 l1.20095 US gal0.160544 ft³
1 UK pt0.568261 l0.150119 US gal0.020068 ft³
1 tbsp0.0147868 l0.00390625 US gal0.00052219 ft³
1 tsp0.00492892 l0.00130208 US gal0.000174063 ft³

l → US gal, ft³ — quick values

lUS galft³
0.5 l0.132086 US gal0.0176573 ft³
1 l0.264172 US gal0.0353147 ft³
2 l0.528344 US gal0.0706293 ft³
3 l0.792516 US gal0.105944 ft³
5 l1.32086 US gal0.176573 ft³
10 l2.64172 US gal0.353147 ft³
20 l5.28344 US gal0.706293 ft³
25 l6.6043 US gal0.882867 ft³
50 l13.2086 US gal1.76573 ft³
100 l26.4172 US gal3.53147 ft³
250 l66.043 US gal8.82867 ft³
1 000 l264.172 US gal35.3147 ft³

How this converter works

The trap in volume is that a US gallon and an imperial gallon are not the same drink: 3.785 l against 4.546 l, a difference of a fifth. Recipes, fuel figures and shipping quotes all suffer from it, so both gallons — and both pints — sit on the page side by side.

Cooking measures are handled too. A US cup is 236.6 ml, a tablespoon 14.79 ml, a teaspoon 4.93 ml. Enter 2 cups and 3 tablespoons together and the millilitre row gives you the number your kitchen scale actually wants.

Notes and abbreviations

  • l — litre, identical to a cubic decimetre; 1 ml = 1 cm³
  • bbl — oil barrel, 158.987 l, the unit crude oil is priced in
  • US gal — 3.785 l; UK gal — 4.546 l. Never assume which one a source means

Questions

How many millilitres in a cup?

236.5882365 ml for a US cup. A metric cup used in Australia and New Zealand is 250 ml — use the millilitre row directly for that one.

Why is UK MPG higher than US MPG for the same car?

Because the imperial gallon is 20.8 percent bigger. The fuel economy converter handles that comparison directly.

Is a litre exactly a cubic decimetre?

Yes, since 1964. An older definition tied it to the volume of a kilogram of water and was 28 parts per million off.

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