Specific Gas Constant Calculator

Calculate the specific gas constant (R) for various gases.

Input Parameters

Common Gas

Molar Mass (M) (g/mol)

Calculation Results

Enter parameters to calculate

About this calculator

Quick Reference

Ru8.31446 J/(mol·K)

MMolar mass in kg/mol

R (Air)287.058 J/(kg·K)

Overview

The specific gas constant (R) is the universal gas constant (Ru) divided by the molar mass (M) of a specific gas or mixture.

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Pro Tips

Universal Gas Constant (Ru) ≈ 8.31446 J/(mol·K).
Molar mass (M) is usually in g/mol. To get R in J/(kg·K), use M in kg/mol (divide g/mol by 1000).
The specific gas constant is used in the Ideal Gas Law: P = ρRT.

Fun Facts

"The specific gas constant for dry air is approximately 287.058 J/(kg·K)."
"Hydrogen has the highest specific gas constant of any gas because it has the lowest molar mass."
"The constant changes if the gas is humid (moist air), as water vapor has a different molar mass than dry air."

Formula: R = Ru / M