When determining the right size, use the European Size Chart (see above), based on four measurements:
A: Bust size
B: Band size
C: Waist size
D: Hip size
Determining the right bra size
You start by determining your band size, which is based on the measurement around your body just underneath your breasts. Then you determine bust size by running the tape measure around the back (where the bra is unclasped) towards the front across both nipples to the breast bone. This measurement is then compared to the band size.
International Size Converting Charts