I usually wear a 30JJ (often 30K in CK), and I love this bra. In the black colourway, it runs big in both the cups and band.The 30J fits more like a 32J, so I need to wear it on the tightest hooks, but aside from that the fit is spot on for me. It gives a great, naturally uplifted shape (the likes of Bravissimo unpadded bras). It has more projection than any other CK bra I've seen, with fairly narrow wires and a low gore. All in all, if only the band was tighter it would be my perfect bra. The only other problem is that it's quite high at the underarms, and the straps are just slightly too wide, so they can irritate throughout the day. It's a minor complaint though! The cup shape is spot on for those with balanced fullness (like myself), though I have read reviews from both bottom-heavy and full-on-top women who have found it worked on them. Definitely worth a try for those sized out of other t-shirt bras!