5'4" | ~160 | Bust 41 [34DDD(F)] | Waist 33 | Hips 36 --- Ordered a Small I usually wear a medium in pants but I tend to dress more than comfortably, baggy and shapeless half of the time honestly. That being said, I took a chance with these but they fit perfectly. They're not even tight and believe me I HATE tight clothes but I LOVE these pants... They have a good amount of stretch. Reminds me of my adidas training pants. And yes ladies, these definitely open all the way up and I do mean all the way. They didn't pop open on me when I sit down though.