Ideal Gas Density Calculator
Estimate ideal-gas density from absolute pressure, molar mass, and absolute temperature. Enter all three values below.
Calculate gas density
Enter pressure, molar mass, and temperature to calculate density in g/L.
Ideal gas density formula
For an ideal gas, density is related to absolute pressure and molar mass, and inversely related to the gas constant and absolute temperature.
ρ = PM / RT
Assumptions and conditions
- The gas is approximated as an ideal gas.
- Pressure is absolute pressure in kPa.
- Molar mass is in g/mol and temperature is in Kelvin.
Frequently asked questions
How is ideal gas density calculated?
Density is calculated using ρ = PM/(RT), where P is absolute pressure and M is molar mass.
What units does the result use?
This calculator reports density in grams per litre (g/L).
Why must pressure be absolute?
The ideal gas equation requires absolute pressure, not gauge pressure.
Why must temperature be in Kelvin?
Kelvin is an absolute temperature scale required by the ideal gas equation.
How to use this calculator
- Enter absolute pressure in kPa.
- Enter molar mass in g/mol.
- Enter temperature in Kelvin.
- Select Calculate density to view the result.
Understanding the result
The result is expressed in grams per litre (g/L). For a fixed pressure and molar mass, increasing the absolute temperature decreases the ideal-gas density.