Bra Size Chart Calculator
This is the whole sizing landscape on one interactive grid: bands across, cup letters down, in whichever of the 7 systems you toggle. Tap any size and its sister diagonal lights up, the sizes sharing that cup volume under different labels.
Seeing the diagonal is the fastest way to internalize how sizing actually works, faster than any paragraph about it.
| Cup \ Band | 28 | 30 | 32 | 34 | 36 | 38 | 40 | 42 | 44 |
|---|---|---|---|---|---|---|---|---|---|
| AA | |||||||||
| A | |||||||||
| B | |||||||||
| C | |||||||||
| D | |||||||||
| DD | |||||||||
| DDD | |||||||||
| G | |||||||||
| H | |||||||||
| I | |||||||||
| J | |||||||||
| K |
Highlighted diagonal = sister sizes sharing the selected size's cup volume. Toggle the system buttons to see the same grid in any of the 7 conventions. Runs in your browser; nothing is stored.
Reading the grid like a fitter
Columns move band size at constant letter: along a row, each step right adds two inches of band with the same printed cup, which means genuinely bigger cups as you go right. The highlighted diagonal moves band and letter in opposite steps, holding volume constant. Once those two directions make sense, every 'is X bigger than Y' question answers itself from the grid.
Toggle to EU or JP and watch the labels change while the highlighted geometry stays put: that is international conversion in one picture. The same physical size wears seven different name tags.
Frequently asked questions
Last updated August 2026.