Finding the perfect bra can sometimes be quite tricky. You know your size, but the bra still doesn’t fit properly. The band is either too tight or too loose, and the cups are too big or too small?

This is where sister sizes come into play. In this article, we’ll explain everything you need to know about sister sizes and provide helpful tips and tricks to find your perfectly fitting bra.

In our sister size chart, you’ll find everything you need at a glance:

Before diving into sister sizes, it’s important to understand how bra sizes work. Bra sizes consist of two components: the band size and the cup size.

The band size is measured in centimeters and increases in 5-centimeter increments, such as 75, 80, 85, and so on. The cup size, on the other hand, is the difference between the bust measurement and the band size.

This means that an A cup with a band size of 75 is not the same as an A cup with a band size of 90.

Sister sizes offer two main benefits: first, they provide an alternative option when your usual size is out of stock or unavailable.

Secondly, they have the potential to perfect the fit of your bra. Even if you’ve found your correct bra size, sister sizes can help optimize the fit with certain styles, providing you with maximum comfort.

Now the question is, how do you determine your bra sister size? We’ll look at the four most common fitting issues and show you simple solutions using sister sizes:

1. The band fits well, but the cups are too small

Go down a band size and up a cup size. For example, if you usually wear a 75B and the cups are too small, try a sister size of 70C.

2. The band fits well, but the cups are too large

Go up a band size and down a cup size. For example, if you normally wear 85C and the cups are too large, try a sister size of 90B.

3. The cups fit well, but the band is too loose

Go down a band size and up a cup size.

4. The cups fit well, but the band is too tight

Go up a band size and down a cup size.

Note: If both the band and cups don't fit properly, sister sizes won’t help. In this case, you need to remeasure your bra size to find your correct fit.

Sister sizes are a helpful way to find a better fit when your regular size isn’t quite right. By experimenting with different band and cup sizes, you can find the perfect fit for you.

With the right sister sizes, you can improve your bra fit and enjoy a more comfortable wearing experience.