A simple meaning of the Charles law formula is when the pressure level on a dry gas remains constant, the volume, along with the Kelvin temperature, will be in a direct proportion. The equation that can be used here will be PV=K. You can learn more about this by looking at the graph of Charles law. The K may remain constant here. The letter P stands for the total amount of pressure, and V denotes Volume. That’s why V=KT. When the temperature increases, the gas volume will also go up accordingly.