Solve the ideal gas law PV = nRT for pressure, volume, moles or temperature — enter any three quantities in SI units and get the fourth. Uses R = 8.314 J/(mol·K).
The ideal gas law PV = nRT links the pressure P, volume V, amount of gas n (in moles) and absolute temperature T through the gas constant R = 8.314 J/(mol·K). It describes real gases well at low pressure and high temperature.
Enter any three quantities and the calculator solves for the fourth. Always use absolute temperature in kelvin (°C + 273.15) and SI units — pressure in pascals and volume in cubic metres — so the value of R applies.
P is pressure (Pa), V is volume (m³), n is the number of moles, R is the gas constant 8.314 J/(mol·K), and T is absolute temperature (K). It relates all four gas properties.
In SI units R = 8.314 J/(mol·K), used with pressure in pascals and volume in cubic metres. If you work in litres and atmospheres, R = 0.08206 L·atm/(mol·K) instead.
The law is derived for absolute temperature. Using Celsius would give wrong (even negative) results, so always convert with T(K) = T(°C) + 273.15.
About 22.4 litres per mole at 0 °C and 1 atm, which follows directly from V = nRT/P.