If bra sizing has ever felt like a math problem, here is some good news: with AirForm you only need one number. AirForm is sized by your band (the number in your bra size), not by cup letters, so finding your size takes about two minutes and a tape measure.
The one number you need
Your band is the number in a standard bra size. In 34C, the band is the 34. AirForm fits cups AA to C within each size, so you choose by band and the cup range is built in.
How to measure your underbust
- Use a soft fabric tape measure. If you only have a string, mark it and lay it flat against a ruler after.
- Wrap it around your ribcage directly under your bust, where a bra band sits.
- Keep the tape level all the way around and snug, but not squeezing.
- Breathe out and read the number in inches. That is your underbust measurement.
Tip: measure without a bra on, or with a thin unpadded one, for the most accurate reading.
Match it to your AirForm size
| Size | Your under bust (in) | Example bra sizes |
|---|---|---|
| S | 28–31 | 28AA, 30A, 30C |
| M | 32–34 | 32B, 34B, 34C |
| L | 35–36 | 36A, 36B, 36C |
| XL | 37–40 | 38A, 40B, 40C |
So if you normally wear a 34C, you are an M. A 36B is an L. You can always check the full size guide on the product page.
If you are between sizes
Size to your band measurement. Because of the fixed-cup design, sizing up adds band room, not cup room, so going up a size will not give you more space in the cup. Stay true to your band for the best fit.
If you are a D cup or larger
AirForm currently fits up to a C cup, so this style will not fit a fuller cup yet. A fuller-bust version is in development. Follow us on TikTok and we'll announce it there the moment it launches.