Bra Size to Bust Size Chart: Approximate Reference
A quick reference showing how underbust, bust difference and starting cup size relate. Use measurements as a starting point and verify fit in the garment.
Approximate Bust Reference by Band
The table uses the site's simple one-inch cup-difference convention. Values are approximate reference points rather than guaranteed body measurements for a labeled bra size.
| Band | Approx. Underbust | A | B | C | D | DD | DDD/F |
|---|---|---|---|---|---|---|---|
| 30 | 29–31" | 31" | 32" | 33" | 34" | 35" | 36" |
| 32 | 31–33" | 33" | 34" | 35" | 36" | 37" | 38" |
| 34 | 33–35" | 35" | 36" | 37" | 38" | 39" | 40" |
| 36 | 35–37" | 37" | 38" | 39" | 40" | 41" | 42" |
| 38 | 37–39" | 39" | 40" | 41" | 42" | 43" | 44" |
| 40 | 39–41" | 41" | 42" | 43" | 44" | 45" | 46" |
Frequently Asked Questions
Answers about sizing methods, measurements, and fit considerations.
Can two people with the same bust circumference wear different bra sizes?
Yes. Bra size depends on both ribcage and bust measurements, and fit also depends on breast shape and the construction of the bra.
Sources & Standards
- ISO 8559-1:2017, Size designation of clothes — Part 1: Anthropometric definitions for body measurement
- White & Scurr (2012), Ergonomics, DOI 10.1080/00140139.2011.647096