How to calculate the efficiency of MOSFETS?

I am calculating the efficiency of the MOSFETS using a switch loss calculator probe. It calculates using the switching losses from the MOSFET and input source ( 1-Ploss/Pin). The value that I am getting is too high at 99.84 and above, do I consider this efficiency to be accurate and consider the values? As I am using the efficiency of the mosfets to validate my switching losses.

We are happy to give some feedback, but this is far too little information for anyone to help. Can you include your model and thermal description files here?