Basically, they are sizing groups, equivalent to bra sizes, that are based on cup volume. And the volume of cup size varies with the band width. It's easy to calculate your sister bra size. If ...

Your bra size is made up of your band size and your cup size. ... You can refer to this chart to understand sister sizes further. Ultimately, what matters is that you find a bra that feels good.

The overbust measurement will tell you your cup size.” Step 4. Check a bra size chart to make sure everything is up to snuff. Here’s one provided by Hanro for reference. Hanro. Step 5.

We turned to experts to explain how to measure your bra size at home, what to know about the cups and the band and more. Shop our top brands for bras, too.