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How to Measure Bra Size for a Perfect Fit

Buying Guide

A proper-fitting sports bra is essential to getting the most out of your workout. Here's how to measure your size and ensure the right fit.

Last updated: May 16, 2022
5 min read
How to Measure Bra Size for a Perfect Fit

For female athletes, a comfortable and supportive bra is foundational to an effective workout. The right sports bra not only prevents bounce during burpees and chafing as you sweat, but can also reduce back pain and improve posture. An ill-fitting bra, on the other hand, can cause discomfort, especially for women with larger breasts. In fact, a study of women seeking breast reduction surgery to relieve their symptoms found that nearly every participant was wearing the wrong bra size.

If you feel your bust is distracting you from your fitness goals, you're not alone. Many women report that breast issues are a barrier to physical activity. But finding the right sports bra fit with enough support may be just the game changer you need to get comfortable with a rigorous workout routine. It all starts with taking the right measurements to calculate your size.

How to Find Your Bra Size

It's best to take measurements while wearing a non-padded, good-fitting bra. But if you're not sure if your current bras fit, you can take measurements while you're not wearing a bra. Here's how to get both your traditional bra size and your sports bra size, step by step.

  1. 1.How to Measure Your Band Size

    To get your band size, start by using a measuring tape to find the circumference of your ribcage just under your bust. Make sure you breathe out and wrap the measuring tape snug against your body, with just enough space to slip two fingers underneath. Round down to the nearest whole inch if you're in between. Then, use the chart below to find your band size.
    How to Measure Bra Size for a Perfect Fit
  2. 2.How to Measure Your Cup Size

    Stand up straight with your shoulders relaxed and breathe out. Wrap the measuring tape loosely around the fullest part of your bust, just over your nipples. Make sure you keep the measuring tape straight across your back.

    Your cup size is the difference between your ribcage measurement and your bust size, so get ready to do a little bit of simple maths. Just subtract your actual ribcage circumference (not your band size) from your bust measurement, and find the answer in the chart below. It's best to round up if you're in between sizes.

    How to Measure Bra Size for a Perfect Fit
  3. 3.How to Find Your Sports Bra Size

    Sports bras are typically sized a bit differently than regular bras. For example, Nike sports bras run from size XS-3X. If you're ordering a Nike sports bra, you'll need to measure your halter in addition to your ribcage size. Wrap the measuring tape around your neck and measure the distance from the fullest part of one breast to the other. You'll get a more accurate measurement with your arms down at your sides, so you may want to ask a friend or partner to help. Once you have both measurements, use the chart below to find your sports bra size.
    How to Measure Bra Size for a Perfect Fit

How to Check if a Bra Fits

Even if you measure your body properly, you might find variations in how different brands or styles fit you. And breast size can change over time due to weight changes and pregnancy. Those may be reasons behind research that shows that as many as four out of five women wear the wrong bra size.

It's important to test the fit of your sports bra before wearing it for your workout. Nike offers US customers an extended 60-day returns policy and free returns for Nike Members (policies vary by country). Here's what to look for in a good-fitting bra:

  • Check that the straps are snug enough to provide support, but allow for two fingers to fit comfortably between the strap and your shoulder.

  • Make sure the band stays put when you lift your arms, without constricting your breathing.

  • If the bra has underwire, make sure the sides stay behind your breast tissue and the entire wire is flush with your skin.

  • If the bra has cups, make sure they are the right size for your breasts. If your breasts spill out of the top of the bra, the bra is too small. If you notice gapping or bunching, the bra is too big.

Choosing the Right Sports Bra for You

Your activity will dictate how much support you need for your sports bra. Here's how Nike sports bras compare, so you can choose the right level for your workout:

  • High Support: these bras are built for vigorous activity, such as running or high-intensity intervals (HIIT) workouts, and women with B-G cup breasts.

  • Medium Support: often the best of both worlds, these bras provide freedom of movement but are strong enough to support most cup sizes as well.

  • Light Support: these bras are soft, comfortable and ideal for women with smaller breasts. They're also great for everyday wear and can feel like a second skin. They'll hold your chest in place for activities like yoga, but may not provide sufficient support for plyometric moves.
How Often Should You Measure Your Bra Size?
You should measure your bra size about every six months as a general rule. But any time you experience weight changes or hormonal changes, it's a good idea to check your size again. Some women notice such profound changes in breast size during their menstrual cycles that it makes sense to own two different size bras.
How Often Should You Replace Your Sports Bras?
It's a good idea to replace your sports bras every 6 to 12 months or whenever you notice that they aren't as supportive as they once were. However, proper bra care can extend the lifespan of your sports bras.

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