This page shows the Gas pressure kPa formula for calculating the pressure of a gas. To identify the gas pressure, the Ideal gas law is used which states that PV = nRT, where P is the pressure in atmospheres, V is the volume in liters, n is the number of gas particles in moles, T is the temperature in Kelvin and R is the ideal gas constant (R = 0.0821 liter atmospheres per moles Kelvin). Substitute the values of n, R, T and V in the formula and do the necessary operations to get the result