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How To Measure Your Sports Bra Size

"What is the right bra size for me?" You might find that when buying a sports bra, this is the question that troubles you the most. Well, you're not the only one who is trying to find the solution! Actually, a number of factors, including pregnancy, weight fluctuations, and nutritional changes, are likely responsible for your changing bra size. 

Therefore, it's best to take another measurement of your bra size once a year or anytime your body goes through a significant shift.

80% of women wear the wrong bra size simply because they're not sure how to measure themselves, but those days are behind you now! We're here to help you find the right sports bra that will make you feel and look fabulous!

Read our simple guide to how to calculate sports bra size below and discover the best sports bra for your workouts and yoga sessions!

Why is it important to have a good sports bra for workouts?

Your breasts move in a figure-eight pattern when you're jogging, occasionally rising and falling by as much as eight inches. Your Cooper's ligaments, which are slender bands of connective breast tissue that support your breasts, are put under a great deal of strain as a result. You're likely to feel sore if you don't have the right support, and you run the risk of doing long term damage.

University of Portsmouth sports scientists looked at the effects of jogging on breast tissue while using different types of sports bras and everyday bras. They discovered that while sports bras with low to medium impact diminish bounce, they are ineffective at reducing the side-to-side movement that occurs when jogging.

In fact, their research demonstrates that depending on the type of bra worn, women run differently. Therefore, a decent sports bra will not only give you essential support, but it may also enable you to achieve a new personal best.

Sports bra fitting guide

Step 1: Rib cage measurement

Measure the circumference of your ribcage, directly below your breasts. The soft tape measure needs to be tight but loose enough to allow two fingers to fit underneath. To the nearest whole inch, round down.

Find the band size that corresponds to your rib cage measurement using the table below.

Step 2: Bust measurement

Take your bust measurement around your breast's largest area. Once more, the tape measure should be snug but not too tight to make breathing difficult.

Step 3: Cup size calculation

Take the difference between your bust and rib cage measurements. The difference is the cup size. Round up if you're in between sizes.

Alternatives to measure bra size

For fit, try a few different cup sizes. Without gaps or creases, cups should fit snugly and securely without being too tight to cause your breasts to protrude over the side or over the top of them.

What level of support do I need?

Three levels of support are available in sports bras: low, medium, and high impact. Your cup size and the kind of workout you undertake will determine the type you need.

Low and medium impact sports bras

These sports bras are designed to give you support for exercises such as yoga, cycling and strength training.

Low-medium impact sports bras usually have no cups and limit movement by squeezing the breasts firmly against the chest wall.

High impact sports bras

For high impact activities such as running, aerobics and mountain biking.

High impact bras are designed to enclose and support each breast with a defined cup shape, similar to that of a conventional bra. To provide the most support, certain high impact bras will combine compression and encapsulation technologies.

Tips for getting the correct bra size

Tight but breathable

You should be able to fit two fingers between the straps and your shoulders in a sports bra, which should be more restrictive than a conventional bra in terms of fit but not breathing space.

No wrinkling

The cup's material should be smooth. Usually, wrinkles in the cloth indicate that the cup is too large. On the other hand, if you're spilling, the cup is too small.


Any underwire should not dig in or pinch your breast tissue; it should instead lay flat against the rib cage underneath it.

Check the straps

Put your hands in the air above your head. Although it's possible that the straps or the back closure may need to be adjusted, if the band rides up, it's usually a sign that the garment is too big.

Treat Yourself to a New Sports Bra Today…

At Loony Legs, we have matching pairs of sports bras and leggings so you can look and feel your best in and out the gym!

Choosing a pair of leggings doesn't have to be a chore, either. With a huge range of funky patterns and colours, we're sure you'll find the perfect pair to match with our super comfortable sports bras.

Shop our collection now and get free shipping over $100 / £77!

How to measure sports bra size FAQs

What is the perfect fit for a sports bra?

Simply fasten a comfortable-feeling clasp to your sports bra. The band and your chest should be close enough to allow two fingers to pass through without discomfort. The band is too tight if you are unable to. It is too loose if you can slip more than two fingers.

Should a sports bra be one size bigger?

The majority of women make the error of selecting a band and cup size that are larger than what they actually require. The majority of the support for your chest actually comes from the band that surrounds your rib cage. It should fit flat against your skin, right below your breasts, and be more restrictive than your typical bra. 

Do sports bras get looser over time?

They do stretch if it feels too tight at first. If you want your sports bra to last longer, it's ideal to choose a tighter fit (as long as it's not uncomfortably tight) and let it stretch up gradually.








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