The Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET) is the most used semiconductor device today. With high yield, low cost and dense packaging is considerations that have pushed the MOSFET to the status of the most widely used device in information technology hardware. This paper effects of varying oxide thickness have been analyzed on oxide capacitance. The p well MOSFET device has been designed and simulated using 80 nm technologies with TCAD tool. The oxide thickness has been varied from 10 nm to 11nm and its effects on oxide capacitance has been analyzed.