Volume is one of the most frequently converted physical quantities — whether you're buying fuel abroad, following a recipe, ordering concrete, or calculating a tank's capacity. Different countries and industries use different units, which can be a major source of confusion. This guide explains all the key volume units and provides ready-made conversion factors.
Basic SI volume units
The base unit of volume in the International System of Units (SI) is the cubic meter (m³). In everyday life we more often use smaller units:
- 1 m³ = 1000 liters = 1,000,000 milliliters
- 1 liter (L) = 1 dm³ = 1000 mL = 100 cL
- 1 milliliter (mL) = 1 cm³ = 0.001 L
- 1 deciliter (dL) = 100 mL = 0.1 L
- 1 centiliter (cL) = 10 mL = 0.01 L
Imperial units — gallons, quarts, pints
English-speaking countries (US, UK, Canada) commonly use imperial units. Note: the US gallon and the UK (imperial) gallon are different values!
- 1 US gallon (gal) = 3.785 liters
- 1 imperial gallon (UK gal) = 4.546 liters
- 1 US quart (qt) = 0.946 liters = 1/4 US gallon
- 1 US pint (pt) = 0.473 liters = 1/8 US gallon
- 1 UK pint (pt) = 0.568 liters
- 1 US fluid ounce (fl oz) = 29.57 mL
- 1 UK fluid ounce (fl oz) = 28.41 mL
Converting liters to gallons and back
The most common conversions:
- Liters → US gallons:
gallons = liters / 3.785 - US gallons → liters:
liters = gallons × 3.785 - Liters → UK gallons:
gallons = liters / 4.546 - UK gallons → liters:
liters = gallons × 4.546
Example: a 60-liter fuel tank = 60 / 3.785 ≈ 15.85 US gallons or 60 / 4.546 ≈ 13.2 UK gallons.
Converting m³ to liters and back
1 m³ = 1000 L1 L = 0.001 m³
Example: a pool 25 × 10 × 2 m = 500 m³ = 500,000 liters of water.
Units used in the kitchen
In cooking you'll encounter additional units, especially in English-language recipes:
- 1 US cup = 240 mL
- 1 US tablespoon (tbsp) = 14.79 mL ≈ 15 mL
- 1 US teaspoon (tsp) = 4.93 mL ≈ 5 mL
- 1 metric cup = 250 mL (the common convention)
- 1 metric tablespoon = 15 mL
- 1 metric teaspoon = 5 mL
Industry-specific units
Various industries use specialized units:
- Oil barrel (bbl) = 158.99 liters
- Cubic foot (ft³) = 28.317 liters
- Cubic inch (in³) = 16.387 mL
- Cubic yard (yd³) = 764.555 liters
Quick conversion table
A handy table for the most common conversions:
- 1 L = 1000 mL = 0.264 US gal = 0.220 UK gal
- 1 US gal = 3.785 L = 128 US fl oz
- 1 m³ = 1000 L = 264.2 US gal = 35.31 ft³
- 500 mL = 0.5 L = 2.11 US cups ≈ 2 metric cups
Use our online volume converter to instantly convert between any units without memorizing formulas.
FAQ — questions about volume converters
How many liters is 1 gallon?
A US gallon = 3.785 liters. An imperial (UK) gallon = 4.546 liters. Always check which gallon your source means — the difference is almost 20%.
How do you convert ml to liters?
Divide the milliliters by 1000. Example: 750 mL = 750 / 1000 = 0.75 L. The other way: liters × 1000 = milliliters.
How many m³ is 1000 liters?
1000 liters = 1 m³. That's the amount of water that fits in a cube with a 1-meter edge.
How do you convert liters to cubic meters?
Divide by 1000: m³ = L / 1000. Example: 5000 L = 5 m³. The other way: m³ × 1000 = L.
What's the difference between a US gallon and a UK gallon?
US gallon = 3.785 L, UK gallon = 4.546 L. The difference is about 20%. When comparing fuel economy (mpg) between the US and UK, this difference matters — a car rated at 30 mpg US is not the same as 30 mpg UK.
How many milliliters are in a cup?
A metric cup (by common convention) = 250 mL. A US cup = 240 mL. In recipes, always check which standard the author is using.
How do you convert cubic feet to liters?
1 ft³ = 28.317 L. E.g. 10 ft³ = 283.17 L. The other way: L / 28.317 = ft³.
How many liters fit in an oil barrel?
1 oil barrel (bbl) = 158.99 liters ≈ 159 L. On commodity exchanges, oil is traded precisely in barrels.
How do you convert cm³ to liters?
1 cm³ = 1 mL = 0.001 L. Divide cm³ by 1000 to get liters. Example: 500 cm³ = 0.5 L = 500 mL.
What's a deciliter and when is it used?
A deciliter (dL) = 100 mL = 0.1 L. It's common in medicine (e.g. blood test results in mg/dL) and in cooking in some European countries.