Find My Bra Size Calculator

Use this free find my bra size calculator to estimate your bra size and sister sizes from underbust and bust measurements.

How the find my bra size calculator works

Band = underbust rounded to the nearest even inch. Cup letter comes from bust minus band. Sister sizes change the band by 2 and the cup by one letter in the opposite direction.

Frequently asked questions

What are sister sizes?

Sizes with a different band and cup that fit similarly, such as 34C and 32D.

Results are estimates for general information only. They are not a substitute for professional advice where applicable. Found a mistake? Report an error.