Gas Density Calculator
Gas Density Calculator: Ideal Gas Law Density Calculation
Gas density affects flow measurement, fan and duct sizing, and buoyancy-driven draft in stacks and chimneys. This calculator applies the ideal gas law to compute density directly from pressure, molar mass, and absolute temperature, a good approximation for air and most combustion gases under typical operating conditions.
The Formula
Density = (P × M) / (R × T)
where P is absolute pressure in Pa, M is molar mass in kg/mol, R is the universal gas constant (8.314 J/mol·K), and T is absolute temperature in Kelvin.
Worked Example
Air at 101.325 kPa and 298 K has a molar mass of 28.96 g/mol.
Density = (101,325 × 0.02896) / (8.314 × 298) = 1.184 kg/m3
How to Use This Calculator
- Enter the absolute pressure in kPa.
- Enter the molar mass of the gas in g/mol.
- Enter the absolute temperature in Kelvin.
- Click Calculate to get the gas density in kg/m3.
Related Calculations
Use with the Flue Gas Density Calculator and Stack Draft Calculator for draft and buoyancy calculations.