I am normally on the smaller side of a 42DD, so I ordered the 42DD and I was able to latch at the tightest hooks and still have some wiggle room. I will be ordering a 40DD to see if that fits better and returning whichever one doesn't work out. The cup sizing fits perfect. It's pretty comfortable besides being slightly too big. The bra has great support with the under wires. I love it and can't wait to see if the 40DD fits better. I will be ordering in more colors!