If your band rides up in the back or your cup is puckering or gapping, it means your bra is too big. A properly fitting bra is straight across the back, and snug against the body. As Koch says, “the tighter, the better,” and she recommends running a finger under the band. No more than one finger should fit under it.

Edmark has another fitting trick. She suggests having a friend or fitter place a hand under the back strap, palm on the back. Then, turn the hand so it’s perpendicular to the back, with only a pinkie finger touching. Next, have the person try to remove his/her hand. If the strap is tight enough at least four fingers will remain stuck under the band.

A too-large cup can easily be swapped for a smaller size, and the cup should lay flat against the breast.