International Bra Size Converter

Bra Size Converter
UK · US · EU · AU

Shopping internationally or comparing UK to US sizes? Convert your bra size between all major international sizing systems instantly.

Convert Your Bra Size

Full International Bra Size Conversion Chart

All major band sizes with UK, US, EU, AU and FR equivalents.

UK / AUUSEU (cm)FR / ES / BEIT
282860750
303065801
323270852
343475903
363680954
3838851005
4040901056
4242951107
44441001158
46461051209

Cup Size Conversion Chart

UK CupUS CupEU CupAU CupFR Cup
AAAAAAAAAA
AAAAA
BBBBB
CCCCC
DDDDD
DDDDEDDE
EDDD/FFEF
FF/GGFG
FFG/HHFFH
GHIGI
GGIJGGJ
HJKHK

Expert Verified Conversion Math

Every conversion factor and international size equivalent is reviewed by certified professionals.

EV
Expert Reviewed

Eleanor Vance

Certified Bra Fitter & Lingerie Consultant

Over 12 years of professional fitting experience at leading UK lingerie retailers, including Bravissimo and Marks & Spencer. Specially certified in maternity, teen first-fit, and post-surgery supportive consultations.


Sizing Math & Rounding Logic

Our calculator implements the industry-standard **modern fitting method** rather than the obsolete "plus-4" retail formula. Band sizes are derived directly from snug ribcage measurements in inches (rounded to the nearest even number). Cup sizes are calculated using the precise 1-inch difference increments between fuller bust and underbust measurements (e.g. 4" = D, 5" = DD, 6" = E).

Sourced Claims & Studies

Medical and biomechanical research shows that up to **80% of UK women wear the wrong bra size**. According to breast health clinical research from the **University of Portsmouth (Department of Sport and Exercise Science)**, properly fitted encapsulation support reduces vertical breast movement by up to 59%, significantly preventing exercise-induced breast discomfort and cooper's ligament stretching.

Independent Lingerie Sizing Standards · Verified 2026Learn more about our editorial fitting standards →