These run small! I usually wear an 18, ordered the 18/20 and the label says 18 (not 20) which would normally be fine but these are definitely a little small. (Not drastically small, these are not Asian sizes or anything) Good price though, so I'll keep these to wear with my PJs and order again a size up to wear out. I would say if you're larger on top (I'm 38DDD) or don't want it clinging to your midsection order a size up.