After personally fitting hundreds of students and working with even more bra sewing pattern customers, I have decided to revise our bra sizing guidelines.
Let’s start with some bra sizing basics. First of all, there is no single sizing standard for bras (or clothing either for that matter). This means that bra sewing pattern sizing differs from company to company, just as it does from one ready-to-wear maker to another.
To further complicate matters, there is no single measurement method to determine what size will work for every body (including the one on my pattern envelope!). As sewists, we know that when you measure around the body, that circumference measurement does not tell us anything about the shapes and curves that are underneath the measuring tape. Of course bras are all about fitting those very shapes and curves.
The only reliable way to determine bra size is to try on finished bras. In the case of ready-to-wear, you just try different bras on until you find the size that works best in the style you like. When sewing, you need to try on finished bras made from that pattern. Of course sewing up all the sizes you want to try on can be quite the task.
Given the bra sizing challenge for everyone sewing their own bras at home, I have long recommend that bra makers start with any new pattern by making their ready-to-wear size – if it fits well! The vast majority of the time I find that students’ well fitted ready-to-wear size and their bra pattern size match up.
Because ready-to-wear generally matches with our bra pattern sizing, we are changing our bra sizing guidance standard to the be, well, what is commonly considered “the standard”. This means that if you need size guidance for our patterns, our guidelines now follow the classic technique:
- Measure body circumference directly under the bust with the tape measure parallel to floor. Round the measurement to the nearest inch, rounding down if you are at the ½” mark. If your measurement is an even number, add 4″, and if it is an odd number, add 5″. This is the band size.
- Measure body circumference at the fullest part of the bust while wearing a bra that is supportive yet out of a relatively thin fabric. Again, keep the tape measure parallel to the floor.
- Derive cup size by subtracting the band size from the full bust measurement. Then consult the chart below to find the cup size. For example, if the full bust is 36″ and the band size is 34″, the difference is 2″. Based on the cup size chart below, this difference corresponds to a B cup. If you are in between sizes, use the larger size.
I still always recommend making a muslin first to test the fit of the bra! This applies not only to new patterns but also to any new fabric you decide to use. I have two posts on how to make muslins (a.k.a. “toiles”), a fast way and a more thorough way.
We updated our Sizing Information page to reflect the above and also added international bra size conversion tables. The sizing section of all our bra sewing patterns will also be updated shortly.
P.S. If you want learn a systematic approach to bra sizing and customizing bra fit, you can enroll in our video course to learn how to fit your own custom bra!