Sports Bra Size Conversion Guide for Fit
Convert sports bra sizes across US, UK and EU systems with band, cup and support-level tips for running, gym training and everyday activewear.
Sports bras are trending with activewear shopping, but sizing can be confusing because brands use both cup sizes and alpha labels. Measure underbust and bust first, then use the Bra Size Converter to compare US, UK and EU equivalents.
Measure Band and Bust
The band should feel firm and level around the ribcage. Measure underbust for band size and bust for cup volume. If the sports bra lists only S, M or L, compare both measurements with the brand's alpha chart instead of choosing your usual top size.
Match Support to Activity
Low, medium and high impact labels matter as much as size. Running usually needs high support, while yoga may need less compression. For band-only comparisons, use the Bra Band Converter to map underbust measurements across regions.
Check Straps and Compression
Adjustable straps help refine fit, but they should not carry all the support. If the band rides up, the band is too loose. If breathing feels restricted, the bra may be too tight or too compressive for the activity. Try movement tests before keeping the item.