Ideal Gas Law Calculator
Solve PV = nRT for the missing variable — pressure, volume, moles, or temperature.
Fill in three; leave one blank.
Solve the ideal gas law
The ideal gas law, PV = nRT, relates the pressure, volume, amount, and temperature of a gas. Give this calculator any three and it solves for the fourth, using the gas constant in litre-atmosphere units.
One mole of gas at 273.15 K (0 °C) and 1 atm occupies about 22.41 litres — the classic molar volume at standard conditions. Leave any field blank and the tool computes it.
Accurate and private
It uses R = 0.082057 L·atm·K⁻¹·mol⁻¹ and solves for whichever variable you omit, all in your browser with nothing uploaded.
Frequently Asked Questions
What units does it use?
Pressure in atmospheres, volume in litres, amount in moles, and temperature in kelvin, with R = 0.082057 L·atm·K⁻¹·mol⁻¹.
Which variable does it solve?
Leave any one of the four fields blank and it solves for that one from the other three.
Why kelvin?
Gas laws require absolute temperature, so temperatures must be in kelvin; add 273.15 to a Celsius value first.
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