basic

Gas Molar Mass from Density Calculator

M = ρRT / P — molar mass from gas density.

Compute the molar mass of an ideal gas from its density, the temperature, and the pressure, using M = ρRT / P (R = 0.08206 L·atm/(mol·K), so input ρ in g/L, T in K, P in atm).

Dr. Helena Ortiz By Dr. Helena Ortiz
Published Last reviewed 1 min read

Inputs

g/L
K
atm

Results

Enter values and click Calculate to see results.
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How to use this calculator

  1. Fill in the inputs above using the units you already have.
  2. Values update automatically as you type — no submit button needed.
  3. Hover any result row for the underlying formula and intermediate values.

Formula

M = ρ R T / P

In depth

Compute the molar mass of an ideal gas from its density, the temperature, and the pressure, using M = ρRT / P (R = 0.08206 L·atm/(mol·K), so input ρ in g/L, T in K, P in atm).