Liters to Milliliters

The liter was introduced in France in 1795 as the volume of a cube 10 cm on each side. In 1901 it was redefined as the volume of one kilogram of pure water at its densest, which turned out to be about 1.000028 cubic decimeters, a tiny mismatch that confused precise work for decades. In 1964 the General Conference on Weights and Measures restored the original meaning, and the liter has been exactly one cubic decimeter ever since.

The liter is not an SI unit itself, but it is accepted for use with the SI. Both a lowercase l and an uppercase L are allowed as its symbol; the capital was approved in 1979 because a lowercase l is easily mistaken for the digit 1.

A milliliter is a cube 1 cm on each side, so 1 mL equals 1 cm³, written cc in medicine and engines. A 1.5 L bottle holds 1,500 cc, and a 2.0 L engine displaces about 2,000 cc. Syringes, IV bags and laboratory glassware are marked in mL, so a liter-sized quantity is usually converted before it is measured.

Water ties volume to mass: 1 L of water is close to 1 kg and 1 mL close to 1 g, which is why a kitchen scale can stand in for a measuring jug when you need, say, 750 mL of water.

Short decimals cause most errors. 0.25 L is 250 mL, not 25 mL, and 0.05 L is 50 mL. In countries that use a decimal comma, 1,75 L means 1.75 L, or 1,750 mL. A useful check is that the milliliter figure must be a thousand times larger, so it always has three more digits before the decimal point.

The reverse is on milliliters to liters. For US gallons, quarts or cups, use liters to gallons or the unit converter.