What is the average pressure inside domestic Pressure Cooker?

Most pressure cooker work at 15psi approximately 107kpa over the existing atmospheric pressure.

The pressure inside the pressure cooker varies with brands. The pressure inside the cooker depends on various factors such as heating appliance, adjustment of the lid, amount of weight used (the weight is placed on the steam vent when steam is being emitted), gasket or sealing ring, safety valve etc. However I am agreed with the answer of Abdul that the average working pressure is around 15 psi pounds of force per square inch.