I am 5 feet 8 inches, 140pounds; Chest 36 inches. I bought 36R and it fits perfectly, no need for adjustment. This slim fit blazer is well tailored for my frame. I am really satisfied with the product. Its a great quality  blazer. The textile isn't thick and heavy and so it works very well for persons like myself who live in a tropical country in the caribbean. I must say that although not thick you can see that the textile is of superior quality wool. It has s a real distinguished look. I have been looking for a long time for a blue blazer (a must have for the fashion savy and the not so savy male) and I got to say I am pleased I got this one.

100% satisfied owner of a
"Tommy Hilfiger Men's Button Vent Trim Fit Blazer"
:-)