Bra Size Guide: US, UK, EU & FR Conversion
Convert bra sizes between US, UK, EU, French and Italian sizing systems with a detailed guide to band and cup measurement differences and tips for finding your correct fit.
Bra sizing is one of the most regionally varied clothing measurements in the world. A US 34C, UK 34C, EU 75C, and French 90C all describe roughly the same physical size, but the way the band and cup are calculated differs across each system. Our Bra Size Converter handles all five major regional systems so you can shop confidently across international lingerie brands.
Band Size Differences Across Regions
The band size is the foundation of bra sizing, and each region calculates it differently. US and UK bands are based on inches — they take your underbust measurement, add 4 or 5 inches depending on the result, and round to the nearest even number. EU bands use the underbust in centimeters directly (a 70 band = approximately 70 cm underbust). French and Spanish bands add 15 cm to the underbust, so a French 90 = roughly EU 75 = US/UK 34.
Cup Size Across Different Systems
Cup size labeling also diverges between systems. While the physical measurement progression (each cup letter = about 1 inch of bust-to-band difference) is universal, the letters assigned to each step vary. UK sizing, for example, continues past DD with E, F, FF, G, GG, H, while US sizing uses DDD/F, G, H, I, J. Our separate Bra Band Converter focuses specifically on underbust-to-band conversion if you already know your cup size and just need the band equivalent.
How to Measure for Bra Size at Home
Take two measurements with a soft tape measure: your underbust (snug around the ribcage directly under your bust) and your bust (around the fullest part without compressing). The difference in inches between these two measurements maps to a cup letter, while the underbust measurement in inches or centimeters maps to the band size. Our converter handles both calculations and outputs the corresponding size across all regional systems simultaneously.