Bra fit is indicated through two basic measurements.
BRA SIZING
Take a snug measurement around the diaphragm under the breasts, and add 4 or 5 inches as indicated in the chart below. Select size from the following chart.
Diaphragm Measurement
From 27" to 28"
From 29" to 30"
From 31" to 32"
From 33" to 34"
Bra Size
32
34
36
38
CUP SIZING
Measure the fullest part of bust holding tape lightly and compare this measurement to your bra size. The difference indicates your cup size.