Bra Size Calculator
Calculate Bra Size
How to Measure
- Underbust: Measure around your ribcage, directly under your bust. Keep the tape level and snug.
- Bust: Measure around the fullest part of your bust. Keep the tape level but loose enough that it doesn't compress your breasts.
Calculation Method
This calculator uses the modern sizing method (also used by Omni Calculator and modern bra fitters). It calculates your band size by taking your snug underbust measurement and rounding it to the nearest even number. Your cup size is then determined by the difference in inches between your bust and your band measurements.
| Difference (inches) | Cup size in the US | Cup size in Australia | Cup size in the UK |
|---|---|---|---|
| <1 | AA | AA | AA |
| 1 (2.5 cm) | A | A | A |
| 2 (5.1 cm) | B | B | B |
| 3 (7.6 cm) | C | C | C |
| 4 (10.2 cm) | D | D | D |
| 5 (12.7 cm) | DD/E | DD | DD |
| 6 (15.2 cm) | DDD/F | E | E |
| 7 (17.8 cm) | DDDD/G | F | F |
| 8 (20.3 cm) | H | G | FF |
| 9 (22.9 cm) | I | H | G |
| 10 (25.4 cm) | J | I | GG |
| 11 (27.9 cm) | K | J | H |
| 12 (30.5 cm) | L | K | HH |
| 13 (33 cm) | M | L | J |
| 14 (35.6 cm) | N | M | JJ |
| 15 (38.1 cm) | O | N | K |
| 16 (40.6 cm) | P | O | KK |
| 17 (43.2 cm) | Q | P | L |
| 18 (45.7 cm) | R | LL | M |