Sports Bra Size
To pick a sports bra size, measure your underbust and bust as for any bra, then compare both numbers with the brand’s own chart. Sports bras sold as S, M or L have no common standard, so each brand maps sizes differently. Sports bras sold in band and cup sizes use your normal bra size.
Your measurements and bra size
The calculator needs JavaScript. Without it, use the steps and the size chart below: measure your snug underbust and your bust in inches, round the underbust to the nearest even number for the band, and count one cup letter per inch of difference.
Calculated in your browser. Your last measurements are kept only on this device until you press Clear.
Your starting size
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Sizes vary between brands and styles. Use this as a starting point and try bras on: the band should sit level and feel firm on the loosest hook.
Next: sister sizes explained · convert to other countries · measuring tips
Why there is no single S to XL chart
Letter sizes in sports bras are set by each brand. One brand’s medium may cover a different range of bra sizes than another’s, and some brands size by band only, others by band and cup. That is why this page gives you your measurements and bra size instead of one letter: match them to the chart of the bra you want.
Two kinds of sports bras
- Letter-sized (S, M, L): usually pull-on styles. Use the brand’s chart with your underbust and bust measurements.
- Band and cup sized (32D, 75C): fitted styles with hooks and adjustable straps. Start with your calculated bra size.
Support level
Brands usually label sports bras with a support level such as low, medium or high, and many suggest which activities each is meant for. Higher-impact activities like running and jumping generally call for more support. Check the brand’s own description.
Fit checks for a sports bra
- Jog on the spot: movement should feel controlled and comfortable.
- The band stays in place when you lift your arms.
- Straps do not dig in and the front does not ride up.
- You can breathe deeply without the band pressing.
Frequently asked questions
How do I find my sports bra size?
Measure your snug underbust and your bust. Look up both numbers in the brand’s own size chart. If the sports bra is sold in bra sizes like 34D, use the size from the calculator.
Is a sports bra size the same as my bra size?
For sports bras sold in band and cup sizes, start with your usual size. For S, M and L styles there is no fixed link, so use the brand’s chart with your measurements.
Should a sports bra be tight?
It should feel firm and supportive but not painful, and you should be able to breathe deeply. If it leaves deep marks or restricts breathing, try the next size or a different style.
What if I am between two sizes in S, M, L?
Check whether the brand gives advice for in-between sizes, and try both if you can. The one that stays in place when you move without pressing too hard is the better fit.
How do I know when a sports bra is worn out?
When the fabric loses its stretch, the band feels looser or it no longer holds you the way it did. How fast that happens depends on how often you wear and wash it.
Why does the calculator not give S, M or L?
Because there is no shared standard. Any single chart would be wrong for many brands. Your underbust, bust and bra size are what every brand chart asks for.
Last updated: October 15, 2026