Ideal Gas Law Calculator Ideal Gas Law Calculator Solve for one variable in PV = nRT by providing the other three. * Use R = 0.0821 L·atm/(mol·K). Step 1: Enter Your Data Variable to Solve For: Pressure (P) Volume (V) Moles (n) Temperature (T) Pressure (atm): Volume (L): Moles (mol): Temperature (K): Calculate Unknown Variable Calculation Result Recalculate