Ideal Gas Law Calculator (PV = nRT)
Solve the ideal gas law, PV = nRT, for pressure, volume, moles, or temperature, using R = 8.314 J/(mol·K) and SI units (Pa, m³, mol, K).
Moles (n = PV / RT)
0.999432 mol
Ideal gas law: PV = nRT, R = 8.314 J/(mol·K). Use SI units: Pa, m³, mol, K. Convert °C to K by adding 273.15. Defaults are 1 mole at STP (≈ 22.4 L).
Frequently Asked Questions
What is the ideal gas law?
The ideal gas law is PV = nRT, relating pressure (P), volume (V), amount of gas in moles (n), and temperature (T). R is the universal gas constant, 8.314 J/(mol·K). It describes the behaviour of an ideal gas.
What units should I use?
Using SI units keeps R = 8.314 J/(mol·K): pressure in pascals (Pa), volume in cubic metres (m³), amount in moles (mol), and temperature in kelvin (K). Remember to convert Celsius to kelvin by adding 273.15.
How do I find the number of moles?
Rearrange to n = PV / (RT). Multiply pressure by volume, then divide by R times the absolute temperature in kelvin.
How do I find temperature from the ideal gas law?
Rearrange to T = PV / (nR). The result is in kelvin; subtract 273.15 to convert to degrees Celsius.
What is the value of the gas constant R?
The universal gas constant R is 8.314 J/(mol·K) in SI units. Other common forms are 0.08206 L·atm/(mol·K) and 8.314 L·kPa/(mol·K).
When does the ideal gas law break down?
It is most accurate at low pressure and high temperature. At very high pressure or low temperature, real gases deviate because molecular size and intermolecular forces become significant.