Accurate Bra Size Calculator
Find your true, comfortable bra size using the gold-standard 6-measurement method across all major international sizing systems.
6-Point Measurements
Measure directly on bare skin without a bra.
1. Underbust Measurements
2. Bust Measurements
Alternative Sister Sizes
- The band sits completely parallel to the floor around your ribcage without riding up.
- The center gore (wires in the middle) sits flush against your sternum.
- Wires fully encompass all breast tissue without resting on breast tissue at the sides.
Why 80% of Women Wear the Wrong Bra Size
Bottom Line: Traditional bra sizing often adds 4 inches to the underbust (+4 method), resulting in bands that are too loose and cups that are too small. The 6-measurement method measures breast tissue accurately in three dimensions (standing, leaning, and lying) to deliver an exact, supportive fit.
Over 80% of individuals wear an incorrect bra size, most commonly wearing a band that is too loose and a cup that is too small. Correct measurement provides 85–90% of breast support from the ribcage band rather than the shoulder straps.
International Band Sizing Cross-Reference Chart
Convert underbust ribcage measurements across major global lingerie sizing standards:
| Snug Underbust (cm / in) | US / UK Band | EU / International Band | France / Spain | Australia / NZ |
|---|---|---|---|---|
| 63 – 67 cm (25 – 26 in) | 30 Band | 65 Band | 80 Band | 8 Band |
| 68 – 72 cm (27 – 28 in) | 32 Band | 70 Band | 85 Band | 10 Band |
| 73 – 77 cm (29 – 30 in) | 34 Band | 75 Band | 90 Band | 12 Band |
| 78 – 82 cm (31 – 32 in) | 36 Band | 80 Band | 95 Band | 14 Band |
| 83 – 87 cm (33 – 34 in) | 38 Band | 85 Band | 100 Band | 16 Band |
What Are Bra Sister Sizes?
Sister sizes are bra sizes that have the exact same cup volume despite having different band measurements (e.g. 34C, 32D, and 36B all hold the same volume of breast tissue).