Bra Size Calculator

This calculator estimates bra size based on bust and underbust circumference (bust size) and is available for US, UK, EU, France, Belgium, Spain, Australia, and New Zealand. For accuracy, please specify to the nearest ¼ inch or ½ cm.

Bust Size

Measure around the fullest part of your bust. Keep the tape level but not tight.

Band Size

Measure snugly around your ribcage, directly under the bust (under‑bust).

Fill your measurements and click Calculate.

Note: Sizing conventions vary by brand and style. This tool uses widely used estimation rules (modern band = nearest even inch for US/UK; EU band ≈ nearest 5 cm; FR band = EU+15; JP band ≈ EU; cup steps: US/UK ≈ 1 inch, EU ≈ 2 cm, JP ≈ 2.5 cm starting near 10 cm).