Gas Density Calculator
Works out the density of a gas from its molar mass.
Density
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Grams per litre — g/L
Compared with dry air — times
Reading this —
The formula
density = P × M ÷ (R × T)
Rearranged from the ideal gas law. T is in kelvin. 1 kg/m³ is the same as 1 g/L.
What to watch out for
A gas heavier than air has a molar mass above about 29 g/mol, which is why carbon dioxide collects low down.
Frequently Asked Questions
What is the density of carbon dioxide at 25 °C and 1 atm?
1.799 kg/m³.
How can I get a molar mass from a measured density?
Rearrange it to M = ρRT ÷ P. Mind the units: pascals, kelvin and kg/m³ give kg/mol.