I bought a large Zero RH + Sprinter Duo Short Men's based on Zero RH chart measurements on the website here. I was disappointed when the shorts and socks arrived because they were smaller that I expected including the free gift socks. I tried the shorts and they were too tight and uncomfortable. I recommend buying at least a size larger when you measure yourself. I will return this shorts. I am 511 and 172lbs. I usually buy US shorts advertised waist 32-34 or large.