Sports Bra Size Calculator

How sports bra sizing works

Sports bras are sold in two different sizing systems, and knowing which one you are looking at prevents most ordering mistakes.

Cup-sized sports bras

These use the same band and cup sizes as everyday bras: 32E, 36C and so on. Start with the size you normally wear. The fit will feel firmer because the fabric has less give, but the size on the label should be the same. British brands that specialise in fuller busts, such as Panache, Freya and Shock Absorber, mostly size this way.

S, M, L and dress-sized sports bras

These fit a range of bodies into each size by relying on stretch. They are sized mainly by the band, and each brand draws the lines in a different place. The calculator gives a typical equivalent, but the brand's own chart always wins.

This system has a built-in limit. One size has to cover several cup sizes at once, so the larger your cup, the less precisely it can fit. From around a DD upward, most people get noticeably better support from a cup-sized bra.

Compression, encapsulation and combination

Compression bras press both breasts against the chest and suit smaller cups and lower-impact activity. Encapsulation bras hold each breast in its own cup and suit D cups and above. Combination bras do both, for high impact. The calculator picks between them for you, and the full comparison is in encapsulation vs compression sports bras.

Checking the fit

Judge a sports bra by moving in it. Raise your arms to check the band stays down, jog on the spot, and take the deepest breath you can. The six checks are set out in how a sports bra should fit. If a correctly sized bra feels tight, read do sports bras run small? before sizing up, and if movement is the problem, how to stop bounce in a sports bra.

Buying guides

For what to look for at fuller cup sizes, see best sports bras for large busts. For running and HIIT, see best high-impact sports bras.

When to replace a sports bra

Sports bras work harder than everyday bras and are washed more often, so the elastic tires sooner. Replace yours when the band has to go on the tightest hook to feel secure, when you notice more movement than you used to, or when the fabric has lost its spring. More in how often to replace your bras.

Frequently asked questions

Is my sports bra size the same as my normal bra size?

In cup-sized sports bras, usually yes. They use the same band and cup system as everyday bras, so start with your usual size. Sports bras sold as S, M, L or by dress size use a different system based mostly on your band, and you need the brand's own chart to convert.

Should a sports bra be tighter than a normal bra?

It should feel firmer, because the fabric is less stretchy and the band is doing more work. It should not stop you taking a full deep breath. If you cannot breathe comfortably at the top of a run, it is too tight.

Should I size down in a sports bra for more support?

Not in the cup. A cup that is too small flattens tissue out of the sides and top, and that tissue then moves more. If you want a firmer hold, choose a higher support level or a firmer band with the correct cup.

How do I know if my sports bra fits?

Jump on the spot or jog for a few seconds in the fitting room. The band should stay level, nothing should spill out, and movement should feel controlled. Then take a deep breath to check it is not restricting you.