Ideal Gas Law Calculator
Calculate temperature from pressure, volume and moles using PV = nRT.
Results
The ideal gas law PV = nRT connects pressure, volume, amount and temperature for gases that behave ideally. This calculator solves for temperature given the other three variables. It also estimates gas density assuming the average molar mass of air (28.97 g/mol). Real gases deviate from ideal behavior at high pressures and low temperatures.
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Frequently asked questions
T = PV/(nR) = (1 × 22.414) / (1 × 0.08206) = 273.15 K or 0°C. This is STP by definition.
Boyle's law (P1V1 = P2V2) is the ideal gas law at constant temperature and amount. At 1 atm and 22.4 L, doubling pressure to 2 atm halves the volume to 11.2 L.
At 25°C (298 K) and 1 atm, air density = PM/(RT) = 1.184 g/L. At 0°C it is 1.293 g/L - about 9% denser than at room temperature.
At high pressures (above 10 atm) and low temperatures (near condensation). Real gases like CO2 deviate noticeably above 50 atm. The van der Waals equation provides better accuracy.
Yes, use the total moles of all gases. Dalton's law says each gas contributes partial pressure proportional to its mole fraction. Air at 1 atm has P_N2 = 0.78 atm and P_O2 = 0.21 atm.