Combined Gas Law Calculator

Apply the combined gas law (P1V1/T1 = P2V2/T2) to find the final pressure, volume, or temperature of a fixed amount of gas.

Initial Pressure (P1)

atm

Initial Volume (V1)

Initial Temperature (T1)

°C

Final Pressure (P2)

atm

Final Temperature (T2)

°C

What the combined gas law states

The combined gas law merges Boyle’s, Charles’, and Gay-Lussac’s laws into one relationship, describing how pressure, volume, and temperature of a fixed amount of ideal gas relate to each other.

The formula

The combined gas law is P1V1/T1 = P2V2/T2, where temperatures are in kelvin. This calculator solves for the final volume V2 given initial pressure, volume, and temperature, plus a final pressure and temperature: V2 = (P1 × V1 × T2) / (T1 × P2).

This calculator assumes ideal gas behavior for a fixed quantity of gas and is intended for general chemistry and physics education.

Last reviewed August 2026