P·V = n·R·T R = 8.314 J/(mol·K)

Ideal Gas Law: The four state variables of an ideal gas. This free calculator solves for Pressure, volume, moles, temperature and shows every step.

The physics

The ideal gas law ties together the four state variables of a gas. Its key practical traps are units: temperature must be absolute (the calculator converts °C/°F to kelvin for you), and pressure/volume units must match the gas constant.

Worked example

1 mol at 0 °C (273.15 K) and 1 atm (101,325 Pa). V = nRT/P = (1·8.314·273.15)/101325 = 0.0224 m³ = 22.4 L — the classic molar volume.

Common uses

Engine and HVAC design, scuba and ballooning, chemistry stoichiometry, weather and atmospheric modelling.

Frequently asked questions

What is the formula for Ideal Gas Law?

Ideal Gas Law uses the formula P·V = n·R·T. The four state variables of an ideal gas.

How do you calculate Ideal Gas Law?

Choose which variable to solve for, enter the values you know (in any supported unit), and the calculator substitutes them into P·V = n·R·T and shows every step of the working. It can solve for Pressure, volume, moles, temperature.

Is the Ideal Gas Law calculator free to use?

Yes — every Physics Fundamentals calculator is completely free, with no login, no ads and no usage limits.