what size is my exhaust pipe?

I tried a search and could only find threads about upgrading to a bigger size,I need to know the stock size. I am removing my old rusted out rattling muffler,and just replacing it with straight pipe until I get the money for a decent cat back system. Is the diameter the same before and after the muffler? thanks,Ben

Stock is 2.25 going into the muffler and coming out (one is 2.25 inside diameter and one is 2.25 outside diameter I believe. The tailpipe shrinks down to about 2" a little after that though. The stock muffler in and out tubes don't line up though.