Ideal Gas Law Calculator
Enter three quantities to solve the fourth with the ideal gas law.
Molar gas constant R = 8.314462618 J/(mol·K)
Use absolute temperature in kelvin. This ideal model may be inaccurate for real gases at high pressure or low temperature.
Calculated value
At 0 °C and 101.325 kPa, one mole is about 22.414 L.
A QUICK WALKTHROUGH
How to use this tool
- Enter three known quantities and select which quantity to solve.
- Choose pressure, volume, and amount units; temperature is absolute kelvin.
- Review the result and the limits of the ideal-gas approximation.
Absolute temperature and units
Temperature is entered in kelvin because the equation uses absolute temperature. Pressure, volume, and amount can be converted between the listed units; all calculations use Pa, m³, K, and mol.
Ideal model limits
Real gases deviate from PV = nRT at high pressure and low temperature, especially near condensation. This calculator does not estimate real-gas corrections or phase changes.
GOOD TO KNOW
Common questions
Can I enter Celsius?
No. Convert to kelvin first; using Celsius in the equation produces an incorrect result.
When should I not rely on the ideal-gas result?
At high pressure or low temperature, particularly near condensation, intermolecular forces and molecular volume matter.