Sister Sizing is a slightly confusing lingerie term for a simple concept and we’re here to explain it for you!
Sister Sizes are sizes that are similar and can fit your measurements. They are your “bra size equivalent”. Having more than one option to try on can be helpful to find the perfect fit and ensure you are getting a bra that is comfortable.
The idea is if you go down an underband size and go up a cup size, you should have a similar fit. And the same if you were to go up an underband size and down a cup size. Finding a sister size can be convenient if your measured size is unavailable!
For example, if you measure at a size 34D, your sister sizes are 32DD and 36C. They are the sizes directly left and right of 34D size in the chart. These bras hold the same volume, but at a different band size. At 32DD you’d have a much firmer band, whereas 36C would be a more relaxed feel without the loss of support. Your underband should always feel firm but not feel restrictive so be careful when opting for a looser underband if you plan on everyday wear.
It’s important to note, cup size is relative to your band size. If you only go up a band size and don’t also go down a cup size, you won’t be able to achieve a similar fit.
Your sister sizes might not always be a perfect fit. The best fitting bra will usually be the one you measure to. Sister Sizes are a nice option, just in case.
In the chart, find your size, then look at the sizes directly to the left and right of your size to find your sister sizes.