The molar volume, symbol Vm, is the volume that one mole of an ideal gas occupies at a given temperature and pressure.

An ideal gas obeys the ideal gas law, Ideal gas equation
If n =1 mol, the molar volume, Vm, can be calculated by rearranging the ideal gas equation

molar volume where,

Vm = molar volume of an ideal gas, L mol-1or dm3/ mol
R is the ideal gas constant, 8.314 472 J mol–1 K–1
T = temperature, Kelvin, K
P = pressure, kilopascals, kPa

The standard conditions for temperature and pressure set by the International Union of Pure and Applied Chemistry or IUPAC are 0 °C (273.15 K, 32 °F) and 100 kPa. (1 atm)

The molar volume of and ideal gas under standard conditions is 22.71 L

Other molar volumes can be calculated from the ideal gas equation and are shown in the Molar Volume table below

Molar Volume, L mol-1 or dm3/ mol


100 kPa pressure (1 atm)

101.3 kPa pressure (1 atm)

0 °C, 32 °F

22.71 (Standard conditions, IUPAC)


20 °C



25 °C




Molar Mass

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