I am 5'8" and usually a M, but ordered a S. I have a smaller chest and features so I sized down and it fits PERFECTLY. What makes this swimsuit unique is the fabric, it somehow sucks EVERYTHING in but isn't constrictive like spanx and I can actually breathe. You can tell this suit is made for real body types and I could not recommend it more! Don't let the cost deter you, it's completely worth it. I have purchased other suits in this price range and they never last more than one season, stretch...