I wear a medium in shirts and jackets. I always get a large in dry tops though to compensate for layers. However the Creeker seems to run a little bigger than other. I think they add extra room to compensate for the pads. I don't use the pads, it makes me feel like I got football pads on. So basically what I'm saying is try on your usual size and then try on one size down and see what you think. I guess it really depends on if you are going to use it with or without the pads. I would just try the different variations before you buy it. All in all though I stay warm and dry, and that's all that matters. Plus I got room to grow a decent beer belly.