Is your bra not fitting right, even though you know your size? Are the cups too small or the band too loose? Sister sizes might be the solution. Here you can find out how to use them, along with a table and practical tips.
Finding the ideal bra is sometimes not so easy. You actually know your size, but the bra still doesn't fit properly. Is the underband either too tight or too loose, and the cups too big or too small?
This is exactly where sister sizes for bras come into play. In this article, we explain everything you need to know about sister sizes and give you helpful tips and tricks to find your perfectly fitting bra.
What exactly are sister sizes?
Before we go into more detail about sister sizes, it is important to understand how bra sizes are constructed. Bra sizes consist of two components: the underbust measurement and the cup size.
The underbust measurement is given in centimeters and is measured in steps of 5, for example 75, 80, 85, etc. The cup size, on the other hand, is the difference between the bust measurement and the underbust measurement.
Important: An A-cup with an underbust of 75 is not the same as an A-cup with an underbust of 90. The cup size is always relative to the underbust measurement.
What are sister sizes good for?
Sister sizes have two main advantages:
- Alternative if unavailable: If your actual size is sold out or unavailable, sister sizes offer a suitable alternative.
- Perfecting the fit: Even if you know your correct bra size, sister sizes can optimize the fit for certain models and offer you maximum comfort.
Bra sister size table
In each row, you can see bra sizes that have the same cup volume. You can therefore switch within a row; the band will become tighter or looser, while the cup volume remains the same.
| A-Cup | B-Cup | C-Cup | D-Cup | E-Cup |
|---|---|---|---|---|
| 70A | ||||
| 75A | 70B | |||
| 80A | 75B | 70C | ||
| 85A | 80B | 75C | 70D | |
| 90A | 85B | 80C | 75D | 70E |
| 95A | 90B | 85C | 80D | 75E |
| 95B | 90C | 85D | 80E | |
| 95C | 90D | 85E | ||
| 95D | 90E | |||
| 95E |
How to determine your bra sister size
Let's look at the four most common bra fit problems and the appropriate solution using sister sizes:
- Band fits, cups too small: Go down with the number and up with the cup size. Example: Instead of 75B, try 70C.
- Band fits, cups too large: Go up with the number and down with the cup size. Example: Instead of 85C, try 90B.
- Cups fit, band too loose: Go down with the number and up with the cup size. This makes the band tighter while the volume remains the same.
- Cups fit, band too tight: Go up with the number and down with the cup size. This makes the band looser without changing the volume.
Note: If both the band and the cups don't fit properly, sister sizes won't help. In that case, you should re-measure your bra size.
Sister sizes are a helpful option if your conventional size doesn't fit optimally. By experimenting with different underbust and cup sizes, you can find the perfect fit for you and enjoy an even more comfortable feel.
Find your perfect bra
At erlich textil you will find bras and bralettes made with TENCEL™ Modal, cotton, and polyamide, in many sizes and sister sizes. Manufactured in Portugal, Turkey, Hungary, and Germany, designed for maximum comfort.
Discover bras & bralettes | Convert bra sizes
The perfect bra isn't the most expensive one, but the one that fits correctly.
