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Gear and Technology

How your running bra should fit – and everything else you want to know.

Woman wearing Brooks Run Bra

Questions about bras for running? We’ve got you covered. Check out our measuring guide, fit fundamentals, and extra tips to make sure your running bra is ready to run.

How to measure for a sports bra

Being fitted by a bra expert at a running store is probably the best option, but you can also measure your own size at home with just a few tools. But how do you measure for a sports bra? We'll help you with that.

Gather your tools, then get started.

You’ll need a flexible tape measure. It’s also best to wear a bra that doesn’t change your shape — no padding or compression. You can also just skip the bra.

How do I measure my band size?

Measure around your rib cage where the bottom band would sit. The tape measure should feel quite snug. If you get a fraction, round down to the nearest inch. Use this chart to find your corresponding band size based on your measurement.

How do I figure out my cup size?

Measure around the fullest part of your boobs — which may not be the centre — and round up to the nearest inch. Then subtract your rib cage measurement. The difference in inches translates to the letter of your suggested cup size in this chart. If you get a fraction, round up to the nearest inch.

Two women flexing their arm muscles

How should a sports bra fit for running?

Making sure your bra fits is the first step on the road to a great run. The best bra for running in the world won’t truly perform if it doesn’t fit correctly. But how should a sports bra for running fit? And how do you know if the sports bra fits? But don’t worry! Our bra designers have some handy tips to help ensure you’re getting the best out of your bra. Do you have larger breasts. Then you should need some more support for your running bra.

How should the bottom band fit?

Make sure the bottom band is snug and lies flat across your back — not riding up or loose around your rib cage.

How tight should a sports bra be?

Your running bra should be snug but not too tight. Exactly how tight should a sports bra be? Well, it should feel tighter than your everyday bra, but you still want to be able to breathe! Can you slide two fingers in between the straps and your shoulders? That’s how you know it’s a good fit. And how to tell if a sports bra is too small? If you notice red marks on your skin after your run, or you find it hard to breathe whilst you’re working out, then your bra is probably too small. Notice where it feels uncomfortable, as you could be wearing a band size that’s too small, you might need a bigger cup size, adjustable straps, or perhaps the entire bra is too small. So, when you're shopping for a sports bra, take note of the way it feels and how easy breathing feels. Swing your arms around and perhaps do some jogging on the spot. You’ll soon realise how tight a sports bra should fit after getting acquainted with a few different styles.

If the bra has built-in cups, how should they fit?

The cups should fit smoothly — spilling out the sides or front means the cup size is too small, while extra space means the cups are too big. If your bra has removable cups, make sure they’re centered around your boobs and that they’re secure in the bra.

And if your bra doesn’t have cups at all, just ensure that the band isn’t pulling away from your rib cage — this can mean that the bra is too small for your cup size.

Women wearing a Dare crossback run bra
The back of the Dare Crossback Run bra
Brooks Run Bra

Consider buying a seamless sports bra

If you hate the feeling of wires digging into you, or you suffer from chafing on long runs, you might want to consider a seamless sports bra. Honestly, these are the most comfortable sports bras you’ll ever wear and you’ll soon forget that you have one on as the miles tick by.

Seamless running bras, as implied by the name, have no seams which can help to reduce that pesky chafing often caused by seams rubbing against your body as you run. Snug and supportive, these bras offer all the same benefits as a regular sports bra, but they feel great for any activity, from running to lower impact workouts.

Bonus tips sports bra for running

After forty years of making bras for running, we have some extra suggestions about how to deal with some common issues we face as women runners. They may help you to know if your sports bra fits or not.

What’s the best way to deal with bra chafe after running?

Ugh, the dreaded bra chafe from running. Whether your straps dig into your shoulders, you get a red mark below the clasp at the back, or you have chafing under breasts after running, you'll know about it when you hit the shower after your run.

Look out for seamless sports bras, which will help to eliminate chafing at the clasp and where the seams of the bra usually meet. You can also ensure you get the perfect fit for you with a bra that has adjustable straps. Don’t fasten the straps too tightly - remember, you should be able to slide two fingers under the shoulder straps.

Alternating running bras is a good tactic to reduce friction. You might run in a seamless compression bra one day and a racerback style the next, for instance. This will help to reduce the wear pattern on your skin and ensure the same area isn’t rubbing day after day.

Finally, check out products like BodyGlide and Vaseline. Smearing a generous amount under your breasts, around your back and on your shoulders before you put on your bra can work wonders for reducing friction and, subsequently, reducing bra chafing when running.

After your run, if you notice you’ve suffered from chafing even with these preventative measures, take a lukewarm shower and wash the area gently to avoid upsetting your already irritated skin. Then gently pat yourself dry - avoid rubbing at all costs! - and apply a rash cream before getting dressed.

Changing out of a sweaty, tight sports bra is the worst — is there anything I can do?

Changing into and out of your run bra should be easy. If pullover bras don’t work for you, try styles with adjustable back closures, or even zip-front designs.

How do I keep my bra from getting too sweaty?

Get rid of boob sweat for good with styles that include mesh panelling, perforated cups, or strappy styles that minimise coverage.

How to wash a sports bra

Look after your sports bra and it’ll look after you. First things first, how often should you wash a sports bra? Ideally, you should be washing your bra after every workout, especially for high-impact workouts like running where you’re likely to sweat a lot. This will remove odours, reduce the likelihood of you breaking out in spots, and prolong the life of your bra.

Now, how to wash a sports bra? You can pop it in your washing machine along with the rest of your sports gear. Before you throw it in, fasten all the clasps and put it in a lingerie bag to avoid it getting caught on other clothes. Then simply follow the care instructions on your bra, using a regular detergent - but avoiding fabric softener, which can damage the sweat-wicking properties of your bra. You can also wash your bra by hand if you prefer. Either way, be sure to dry your bra flat and avoid putting it in the tumble dryer, which can degrade the elastic.

the back straps of the Dare Crisscross run bra

Do bra seams all have to be so irritating?

Bras with a nearly seamless finish or bonded finish — a fancy way of saying seams are adhered with heat instead of stitched — help eliminate seam-on-skin irritation.

What’s the best way to get smooth coverage over my nipples?

Stay confident in your coverage with styles that feature built-in moulded cups or removable cups.

How long does a sports bra last?

Like running shoes, sports bras unfortunately don’t last forever. The main purpose of a sports bra is to protect your breasts from the high impact action of running, reducing bounce - but with every wash, the technical fabric loosens slightly meaning it eventually doesn’t offer the support you need. So, how long does a sports bra last? They tend to perform at their best for around 30-40 washes, after which they’re not as effective.

With that in mind, how often should you replace your sports bra? About every 6 to 12 months is right - or as soon as you start to notice a decrease in the amount of support it offers. If you wear the same bra for every run, you’ll have to replace it sooner, but if you rotate your bras, each one should last for longer.

Need extra help getting started?

Now that you’re armed with all our best advice about running bras, you can use our Store Finder to treat yourself to an in-store fitting, get matched with your perfect Brooks Run Bra using our Bra Finder, or skip straight to the fun part and shop all our run bras. Or learn more about the running bra myths.