n-type mosfet calculate AD AS PD PS
You are asking about the geometry of the transistor. You need to look at the actual layout of the device to get these parameters. If you haven't done a layout yet you can use the design rules to get a good estimate.

Using the design rules, the minimum length of a drain/source region might be the sum of:


the minimum space from a contact to the gate poly
the minimum size of a contact
the minimum overlap of a source/drain diffusion around a contact