Wear a well-fitting bra or supportive top with minimal padding
Stand straight with shoulders relaxed and arms at your sides
Measure underbust (band measurement): wrap a soft tape snugly under the bust; keep it level; record the measurement in inches or cm
Measure full bust (overbust): wrap the tape around the fullest part of the bust; keep it level and parallel to the floor; do not pull the tape too tight; record the measurement
Subtract underbust from full bust to determine cup size (in the same units)
Use the bra size chart to match the cup size to the difference for your measurement system (inches or cm)
Confirm band fit: the band should sit level and feel snug; when you lift your arms, it should not ride up significantly
Recheck cup fit: cups should fully cover the bust without gaps, overflow, or excessive wrinkling
If between sizes, choose the size that gives the best band snugness and smooth cup coverage, then fine-tune with sister sizes