Ideal gas law calculator
Fill in any three of pressure, volume, amount of gas and temperature. Leave one box empty and it is calculated from PV = nRT.
How the numbers are worked out
The ideal gas law is PV = nRT, with R = 8.314462618 J/(mol·K), the exact value fixed by the 2019 redefinition of the SI base units. Inputs are converted to pascals, cubic metres, moles and kelvin, the missing quantity is solved, and the result is shown in all common units. The law describes an ideal gas; real gases at high pressure or low temperature deviate from it, so treat results near liquefaction as estimates. The pre-filled values (101.325 kPa, 0 °C, 1 mol) give about 22.414 litres, the molar volume at the older standard conditions of 0 °C and 1 atmosphere. Temperatures must be above absolute zero, and pressure, volume and amount must be positive.