Estimate your bra size from underbust and overbust measurements (in inches). Results are an approximation — fit varies by brand.
Snug measurement around your ribcage
Loose measurement around the fullest part
30E
US size
30E
UK size
6.0 in
Cup diff
How it works: cup size comes from bust minus band measurement. Each inch roughly = one cup size (AA=½", A=1", B=2", C=3", etc.). Try several sizes — sister sizes (one band up, one cup down) can fit similarly.