Calculate ideal gas law

Solve pressure, volume, amount, or absolute temperature with the ideal-gas equation.

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ToolIdeal Gas Law Calculator
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How it works

The equation pV = nRT relates pressure, volume, amount, and absolute temperature; three quantities determine the fourth by rearrangement. The gas constant must match pressure and volume units.

  • Temperature is required in kelvin.
  • No compressibility factor is added.

Worked example

Molar volume at STP
1 mole of gas at 1 atm and 273.15K, volume left blank
Input
											Moles: 1
Pressure atm: 1
Temperature k: 273.15
Output
												Pressure atm: 1
Volume litres: 22.414
Moles: 1
Temperature k: 273.15

When to use this

Chemistry exercises find moles, gas-cylinder estimates convert pressure and volume, and labs compare real gases with the ideal model.

Edge cases

  • 25 means 25 K, not 25 °C.
  • High pressure or low temperature can depart from ideal behaviour.
  • L·atm and joule gas constants require unit conversion.

References