Chemistry
Molar Mass of Gas Calculator
Work out the molar mass of a gas from the mass, pressure, volume and temperature of a sample using the ideal gas law.
Your inputs
Change any value to update the result instantly.
Molar mass of the gas
1 g/mol
Amount of gas
1 mol
Absolute temperature
273.15 K
Gas density
0.0446 g/L
Molar volume at these conditions
22.414 L/mol
Ideal-gas approximation. Results drift from reality at high pressure or near the condensation point.
What this calculator does
Determines the molar mass of a gas from the measured mass, pressure, volume and temperature of a sample.
What your result means
The molar mass in g/mol obtained by rearranging PV = nRT with n = m / M. Comparing it with candidate formulas helps identify an unknown gas.
Formula and working
M = (m × R × T) ÷ (P × V)
- 1
Collect the inputs
Mass of the gas sample (m) = 1 g; Pressure (P) = 101.325 kPa; Volume (V) = 22.414 L; Temperature (T) = 0 °C
- 2
Apply the formula
M = (m × R × T) ÷ (P × V)
- 3
Result
Molar mass of the gas = 1 g/mol
Frequently asked questions
Symbols and assumptions
- m
- Mass of the gas sample in g
- P
- Pressure in kPa
- V
- Volume in L
- T
- Absolute temperature in K
- R
- Gas constant, 8.314462618 J/(mol K)
- • The gas behaves ideally over the measured range.
- • Temperature is converted to kelvin; pressure in kPa with volume in L gives energy in joules directly.
Sources and review
Reviewed 2026-09-22 · Next review 2027-09-22
- • Real gases deviate at high pressure or close to condensation, where the calculated molar mass will be off.
Important limitation
This is an educational estimate based only on the values and formula shown. Verify current rates, rules, units, and professional standards before relying on the result. It is not personalized financial or investment advice.
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