All About Bra Cup Size


How should the cup fit?

The cup of a bra is designed to surround and support the breast tissue.

For an underwire bra, the wire should surround the breast tissue, but not sit on top of it. If you feel your wire digging into you, it is likely too small. When the wire fits properly, you should barely feel it.

With a wire free bra, the support band or seaming of the bra should surround the breasts in the same way a wire would.

For the wire to work properly, it must be held in place by the band of the bra. Throughout the day, your band is responsible for keeping the wires firmly against the body so they do not poke or rest on the breast tissue. Check out How Should My Bra Band Fit for more information.

Checking your cup size

The first thing to do when checking your cup size is to be sure the breast tissue is as far into the cup as possible.

You can do this by sweeping the breast forward with one hand while pulling the wire back under your arm with the other hand. Set the wire in place and then let the breast tissue fall into place.

You can also lean forward and hold both wires away from your body while letting the breast drop into the cup. Then pull the wire back and set into place before straightening up. Once your breast is pulled forward, if the tissue is not completely in front of the wire, you need to go up in your cup size. For every 3/4 inch of breast tissue under and behind the wire, go up one cup size.

If you have never been fitted, it is likely that you will need to go up several cup sizes. Don’t let the letters scare you! The average (properly fitted) cup size in the US is a DD.  That’s average.  So, if you consider yourself large busted, you are likely an F, FF, or larger. Likewise, if you consider yourself small chested, that doesn’t mean you are a AA cup.  You could easily be a B, C, or even D cup.

Proper cup fit is influenced by band size. As the band size changes, so does the cup size. For every band size you go down, you should go up one cup. If you are in a 38C with a good cup fit, but want to go down to a 36 band, you would go to a 36D for a tighter band with the same cup fit. Likewise, if you were in a 34DD and wanted to keep the cup fit, but get a looser band, you would want a size 36D.