I am 5'5" and average build so I bought a large so that the pant length would operate as capris. I didn't want a pair that were too short. They are perfect. The outfit itself is baggy but what onesie isn't that way? The material isn't great and you definitely need to wear a cami and tights underneath because the buttons are spaced pretty far apart. The hoodie fits well and the sleeves are perfect for versatile wear both during the winter and summer.