Bra Size Guide: Band & Cup Measurement, Sister Sizes, and Fit Tips

Bra size = Band (number) + Cup (letter). Accurate measurement ensures support, comfort, and health.

How to Measure

1. Band: Snug tape around ribcage, under bust, parallel to floor. Round to nearest even number (e.g., 33→34, 35→36).
2. Bust: Loose tape around fullest part (nipple line), parallel.
3. Cup: Difference (Bust − Band). 1″=A, 2″=B, 3″=C, 4″=D, 5″=DD/E, 6″=DDD/F, etc.

Sister Sizes (Same Cup Volume, Different Band)

Go up band → down cup: 34C ≈ 36B ≈ 38A.
Go down band → up cup: 34C ≈ 32D ≈ 30DD.

Fit Checklist

• Band: Firm, level, 2-finger tension; doesn't ride up.
• Cups: Fully contain tissue; no spill (top/sides) or gaping.
• Gore: Tacks flat against sternum.
• Straps: Stay put; don't dig or slip.
• Underwire: Encloses breast tissue; sits on ribs, not breast.

International Variations

UK, EU, US, FR, AU/JP sizing differ. Use brand-specific charts. Professional fitting recommended annually or after weight/hormonal changes.