Picture this. You are in the trial room and have tried on a million (it sure feels like a million!) bras. One just about fits, most are nowhere close and the couple that you really love, are not available in your size. If this scenario has played out in your life, fret not. I have just the solution for it and it’s called Sister Sizes.
Essentially sister sizes bras have the same cup capacity even though they are different sizes. This is how the bra sizes are related, hence the name sister sizes.
Figuring out your sister size requires you to shift your BRA size in opposite directions in both band and cup size based on which you want to adjust. For instance, if you are a 34B, and the cup is too loose, you need to go down in cup size but go one up in band size to make sure the band also fits you well. That makes your sister size as 32C.
Similarly if you find that the bra band is loose, you will need to go up a cup size but come down a band size. That makes your sister size 36A. One up, one down is the thumb rule.
Here’s a handy chart to find your sister size.
Here’s how to read this chart. Find your ideal bra size that you normally wear everyday. Found? Great. See the two sizes on each side of your size. Take 36C for example. If you are looking for a smaller cup size, your sister size is 34D and 38B if you are hunting for a bigger cup size. As you noticed, the band size also shifts one up or down simultaneously. That’s how you determine your sister size, easy isn’t it?
Pro tip: I recommend buying a sister size only if you are looking for a certain style of bra and are unable to find it in your ideal size. For instance, if you aren’t able to find a balconette bra in your usual size, a sister size might be a good idea. Else, I suggest sticking to your tried and tested size for everyday bras.