Ideal Gas Law Calculator (PV = nRT)

Enter the number of moles, temperature, and volume of a gas to calculate its pressure using the ideal gas law.

Ideal Gas Law Calculator (PV = nRT)

Solve for pressure, volume, moles, or temperature using the ideal gas law.

This calculation assumes ideal gas behavior, which is a good approximation for many gases at standard conditions but becomes less accurate at very high pressure or very low temperature, where real gases deviate from ideal behavior.

The ideal gas law relates pressure, volume, temperature and the number of moles of an ideal gas using the universal gas constant R. This calculator solves for pressure given the other three variables.

Example

  • With the default values shown above, this calculator returns: Pressure ≈ 0.998.

Frequently Asked Questions

What is the gas constant R used here?

This calculator uses R = 0.0820573 L·atm/(mol·K), giving pressure in atmospheres — a different value of R would be needed for other unit systems, such as pascals with cubic meters.

When does the ideal gas law break down?

It becomes less accurate at very high pressures or very low temperatures, where intermolecular forces and the finite volume of gas molecules — ignored in the ideal gas model — start to matter.

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