The six checks
1. The underband
It should sit level on your ribcage, directly under the breast tissue, and feel firm. Slide two fingers underneath. Then lift your arms above your head: the band must stay where it is. If it rides up, it is too loose, and the bra cannot work.
2. Containment
All of your breast tissue should be inside the bra. Look for bulging at the neckline, at the armholes and under the band. In a cup-sized sports bra, each breast should sit fully in its own cup.
3. The straps
They should feel secure without digging in, with room for two fingers. If you need them very tight to feel supported, the band is too loose.
4. Wires and seams
If the bra is wired, the wire should sit on your ribcage and not on breast tissue. Run a hand over the inside seams: anything you can feel now will rub after half an hour.
5. The breath test
Breathe in as deeply as you can. The bra should not stop your ribs expanding. Remember that you breathe harder during exercise than in a fitting room.
6. The bounce test
Jog on the spot, jump, and swing your arms for ten to fifteen seconds. Watch in the mirror and notice how it feels. Movement should be small and controlled, and nothing should shift, gape or need adjusting afterwards.
Quick fixes
| Problem | Likely cause | Try |
|---|---|---|
| Band rides up | Band too big | A smaller band; in cup sizing, cup up one |
| Bulging at the top or sides | Cup or size too small | Cup up; or the next size in S, M, L |
| Fabric wrinkles or gapes | Too big | Cup or size down |
| Cannot breathe deeply | Band too small | Band up; in cup sizing, cup down one |
| Straps dig in | Loose band, or narrow straps | Firmer band; wider or padded straps |
| Chafing under the band or arms | Loose fit, rough seams or damp fabric | Closer fit; flat seams; wicking fabric |
| Too much bounce | Wrong size or too little support | See how to stop bounce |
Differences from an everyday bra
- It should feel firmer. The fabrics stretch less on purpose.
- The centre does not always sit flat. In compression styles there is no separate centre panel.
- Coverage is higher, at the neckline and under the arms.
- Movement is the test. An everyday bra can be judged in the mirror. A sports bra cannot.
The general principles are in how a bra should fit.
Match the bra to the activity
A bra that is right for yoga may be wrong for running. Manufacturers label support as low, medium or high impact. Choose the level for the most demanding thing you will do in it, and the type of construction that suits your cup size: see encapsulation vs compression sports bras.
Frequently asked questions
How tight should a sports bra be?
Firmer than an everyday bra, and never so tight that you cannot take a full, deep breath. You should be able to slide two fingers under the band and under each strap.
Should a sports bra flatten your chest?
A compression bra will, to a degree. It should hold the breasts close without pain, and without tissue being squeezed out at the top, sides or bottom.
How do I know when to replace a sports bra?
When you notice more movement than before, when the band needs its tightest setting, or when the fabric has lost its spring. With regular use and washing that can be within a year.
Not sure which size or type to try?
Use the sports bra calculator →