can a 1/4" make a difference for a drive belt?

I bought a mower from a guy that said it needed a belt and he had one. I just took his word for it and removed the old one then put the new one on. well the trans doesn't disengage when I push the clutch in. I took it off and compared the two and the old one has a slight bit of slack so I put it back on and same thing. so now I have looked up both belts they are listed as 95". I looked in the owners manual that says is the same model as mine and looked up that part number it is 95". then I found a thread on the internet for a tractor with the same model number as mine and their "pro" gives a different part number and when I look that up it is
95 1/4".