Enter the temperature of the gas and the molar mass of the gas into the calculator to determine the root mean square gas velocity.

Gas Velocity Formula

The following equation is used to calculate the Gas Velocity.

Vgas = SQRT ( 3*R*T / M)

  • Where Vgas is the root mean square velocity of the gas (m/s)
  • R is the gas constant (8.3145 J/K-mol)
  • T is the temperature (K)
  • M is the molar mass (kg/mol)

What is a Gas Velocity?


A gas velocity describes the average root mean square velocity the particles of a gas that has a specific density and temperature.

How to Calculate Gas Velocity?

Example Problem:

The following example outlines the steps and information needed to calculate Gas Velocity.

First, determine the temperature (K). In this example, the temperature is found to be 275 K.

Next, determine the molar mass. For this problem, the molar mass is found to be .042 kg/mol.

Finally, calculate the Gas Velocity using the formula above:

Vgas = SQRT ( 3*R*T / M)

Vgas = SQRT ( 3*8.3145*275 / .042)

Vgas = 404.12 m/s