Gas Density Calculator (Ideal Gas)
Gas density calculator from pressure, molar mass and temperature using the ideal gas law.
ρ = p · MR · T
How to use this calculator
- Choose the quantity you want under “Solve for”.
- Type the known values and pick their units: any combination works.
- The result updates as you type. Open “Show the steps” to see the substitution.
ρ = p·M/(R·T). Gases heavier than air (M > 29 g/mol) sink, lighter ones rise.
Formula
ρ = p · MR · T
| Symbol | Quantity | Units |
|---|---|---|
| p | Pressure | Pa, kPa, MPa, hPa, bar, mbar, atm, Torr, mmHg, psi, inHg |
| M | Molar mass | g/mol, kg/mol |
| T | Temperature | K, °C, °F, °R |
| ρ | Gas density | kg/m³, g/cm³, g/mL, g/L, kg/L, lb/ft³, lb/gal |
Constants used: R = 8.314 J/(mol·K)
Worked example
Given: p = 1 atm · M = 28.97 g/mol · T = 0 °C
ρ = p MR T
Result: ρ = 1.2925 g/L
Frequently asked questions
Density of air (29 g/mol) at 0 °C and 1 atm?
About 1.29 g/L.