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Gas Law calculator

Use the ideal gas law to find the pressure, volume, amount or temperature of a gas.

How it works Report a problem

Ideal Gas Law

PV = nRT · Pressure · Volume · Temperature

PV = nRT  |  R = 0.0821 L·atm/(mol·K)

About the Gas Law calculator

Use the ideal gas law to find the pressure, volume, amount or temperature of a gas.

How to use the Gas Law calculator

  1. Choose the unknown under Solve For: P, V, n or T.
  2. Enter the known values: Volume (L), Moles (mol), Temperature (K) and the Gas Constant (R).
  3. Press Calculate.

Formula and method

P V = n R T. With pressure in atm and volume in litres, R = 0.08206 L·atm/(mol·K).

Worked example

1 mol of gas at 273.15 K in 22.414 L exerts a pressure of 1 atm.

Tips

  • Temperature must be in kelvin.
  • Real gases deviate from ideal behaviour at high pressure and low temperature.

Frequently asked questions

What is STP?
Standard temperature and pressure: 0 °C (273.15 K) and 1 atm (definitions vary slightly between organisations).