Bra Size Calculator

How the calculation works

The calculator converts centimeters to inches when necessary, rounds the snug underbust to the nearest even band number, and rounds the difference between full bust and snug underbust to the nearest whole inch. A 1-inch difference maps to A, 2 to B, 3 to C, 4 to D, and so on through the displayed AA–J range. EU bands progress in 5-centimeter steps: for example, a US/UK 32 band corresponds to EU 70, while 34 corresponds to EU 75.

For example, a 32-inch snug underbust and 35-inch full bust produce a 32 band and a 3-inch difference. The starting result is therefore 32C in US/UK notation and 70C in EU notation.

Measure consistently

Use an unpadded bra or no bra, keep the tape parallel to the floor, and breathe normally. The underbust should be snug but not painfully tight. The full-bust tape should touch without pressing the tissue. If a measurement falls between marks, record the more precise value rather than rounding before entering it.

Brand variation and sister sizes

There is no perfectly universal bra-size standard. US and UK cup sequences can diverge above D, and individual brands may use their own grading. Try the suggested size plus nearby options. If the band feels too tight but the cup volume is right, go up one band and down one cup; if the band is loose, go down one band and up one cup. These are sister sizes, such as 32D, 34C and 36B. A sound fit has a level, supportive band, contained cups without gaping or spillover, and a center gore that sits comfortably where the style permits.