A liter (L), also spelled litre, is a unit of volume and capacity in the metric system of measurement. It is not an official unit of the International System of Units (SI), but is still widely used in many countries as an accepted unit within SI. The SI unit of volume is the cubic meter (m3). In terms of SI units:

1 L = 1,000 mL = 1000 cm3 = 0.001 m3

You can think of a liter as the volume of a cube with side lengths of 10 centimeters, where the volume is determined by multiplying the lengths of the sides in three dimensions.

Multiplying the length of each side, we get:

10 × 10 × 10 = 1000 cm3 = 1 L

Liters and SI

As a unit accepted for use with SI, the liter can also be used with SI prefixes. Examples include milliliters, deciliters, decaliters, kiloliters, and more. Adding a prefix to the base unit (liter) indicates a unit that is related to the liter by a power of 10. Using the examples mentioned:

1 L = 103 milliliters = 1000 mL

1 L = 101 deciliters = 10 dL

1 L = 10-1 decaliters = 0.1 daL

1 L = 10-3 kiloliters = 0.001 kL

In everyday contexts, milliliters and liters are the most commonly used forms of the liter; examples include beverages and gasoline.

Did you know?

A liter of water weighs 1 kilogram. Soda can be bought in 2-liter bottles, so a 2-liter bottle of soda weighs about 2 kilograms, or approximately 4.4 pounds.