I am 5’1.5 and 127Lbs. I would have bought a 6 but other comments mentioned going smaller so I got the 4. I think 4 and 6 are the same.First I was surprised at the quality especially in the bust. I was worried the cup size would be small but not at all! The bust area is great quality and it feels like a full bra. Thick padding but not like fake boob padding. Vey supportive. I am a 34C in bra. I was able to cross straps at the back. I will post a pic if I can figure it out.