What is the ideal gas law?

The ideal gas law states PV = nRT, relating pressure (P), volume (V), amount of gas in moles (n), the gas constant (R), and absolute temperature (T).

What value of R does this use?

It uses R = 0.0820573 L·atm·mol⁻¹·K⁻¹, which pairs with pressure in atmospheres, volume in litres, and temperature in kelvin.

Why must temperature be in kelvin?

The ideal gas law requires absolute temperature. Convert from Celsius by adding 273.15. The result panel shows the kelvin value with its Celsius equivalent.

Ideal Gas Law Calculator

Solve PV = nRT for pressure, volume, moles or temperature.

Ideal gas law calculator

The ideal gas law, PV = nRT, links the pressure, volume, amount, and temperature of an ideal gas through the universal gas constant R.

Choose which quantity is unknown — pressure, volume, moles, or temperature — enter the other three, and the result is computed instantly using R = 0.0820573 L·atm·mol⁻¹·K⁻¹. Remember that temperature must be in kelvin and pressure in atmospheres for these units. Everything runs in your browser.