I am a 42 regular 6ft even and 180lb with fairly broad shoulders. I bought the large because I always have worn a large, but the large was too big. Too long in the sleeves and way too much bulk in the body. I exchanged it for a medium and it fits great. Still enough room if I want a fleece on under it, but it has a nice slim fitted fit. Plenty of length in the sleeves, and this is usually a problem for me, even with large. Great jacket!!!