Ideal Gas Law Calculator

Solve PV = nRT for pressure, volume, amount, or temperature — enter any three and get the fourth. Calculates in your browser.

Enter any three, the fourth is solved.

Pressure-
Volume-
Amount-
Temperature-

Show the math

The ideal gas law relates pressure, volume, amount, and temperature:

PV = nRT  (R = 8.314 J/mol·K)

Temperature must be absolute (kelvin): K = °C + 273.15. All math runs in your browser.

What this does

An ideal gas law calculator solves PV = nRT for pressure, volume, amount, or temperature — enter any three and get the fourth.

How to use it

  1. Enter three of the four quantities.
  2. Use absolute temperature (kelvin).
  3. Read the fourth quantity.
  4. Check your pressure and volume units.

How it works

The ideal gas law relates pressure, volume, amount, and temperature. Temperature must be absolute — convert with K = °C + 273.15.

PV = nRT; R = 8.314 J/mol·K

Understanding your result

The one rule that catches everyone is that temperature must be absolute, in kelvin, or the answer is nonsense, so convert from Celsius first. The ideal gas law is an approximation that holds well at everyday pressures and temperatures but drifts for real gases at high pressure or near condensation, where intermolecular forces start to matter.

Example

One mole at 273.15 K and 101.3 kPa occupies about 22.4 litres.

Sources & methodology

Last updated .

Frequently asked questions

What is the ideal gas law?

It relates pressure, volume, amount, and temperature: PV = nRT, with the gas constant R = 8.314 J/mol·K.

What temperature units are needed?

Temperature must be absolute (kelvin). Convert from Celsius with K = °C + 273.15.

Is my data stored?

No. Everything is calculated locally in your browser.