How to Measure Bra Band Size


Your bra band is one important measurement taken when sizing a bra.

The band is the part of the bra that sits beneath the bust and encircles your torso. If your bra fits you correctly, it’s the band - not the shoulder straps - that give you the most support. 

If your shoulders are carrying too much of the weight of your bust, it can lead to discomfort, with bra straps digging into the shoulders. Worse still, and particularly for larger bust sizes, it can cause shoulder and back strain.

Regardless if the bra has an underwire of it's it wireless bra, in order for the band to do its job of providing you support, it’s important to get the right measurement. Too tight and you can feel constricted, with the bra digging into your flesh and even hurting your ribs. Too loose and it won’t give you much support.

Here’s how to measure your bra band:

Measuring Your Bra Band

To get an accurate measurement, you’ll need a flexible / cloth tape measure (the kind that comes in a sewing kit, not the metal kind that comes from a hardware store).

You’ll also want to strip down. Either go bare or wear an unlined/unpadded bra that keeps your natural shape (i.e. not push-up).

To get your band size, use the measuring tape to measure around your torso directly under your bust.

Remember the idea is that you get most of your support from here rather than all the support coming from your shoulders. This prevents too much strain on your shoulders, which can cause short-term discomfort and long-term shoulder strain. 

For an accurate band size measurement, the tape should be level and snug beneath your bust, parallel to the ground. The measurement in inches is your “band size”, according to this method. 

Let’s say you measured 34, add 2. Then your bra size starts with 36.

If the number you measure is odd or a fraction, round up to the nearest even number. E.g. if you measure 33 or 33.5, round up to 34, then add 2. 

This Size Is Not Your Bra Size

Your band size alone does not get you a bra size. The traditional way to measure your bra size and get accurate bra sizing involves taking two measurements and then doing a little bit of math.

The first measurement is the band size, which you’ve just measured.

The second measurement taken when you measure your bra size is your bust measurement.

Second, Get Your Bust Measurement

The second measurement you need - your bust measurement - doesn’t appear in the bra size, but it is used to calculate the cup size.

So, now, using the same measuring tape, measure your bust at the fullest part. If your breasts are fuller at the bottom, it may be easier to lean forward from the waist when you measure your bust at the fullest part. You’ll want to try to have the tape run parallel to where it sat when you measured your band.

Let’s say you measured 38 here.

Finally, Find Your Cup Size

Now, to calculate your cup size, you’ll subtract your band size (the original measurement before adding 2) from your bust size. Each inch represents a cup size, as shown from in the cup size chart below.

For our example, that’s 38 minus 34 (your original measurement), which is 4.

4 inches is a D cup.

So the right bra size according to this method is 36D.

Scroll to view more >>

Bust Size minus Band Size (inches)

Cup Sizes

<1 inch











DD / E











As you shop for bras or attend fittings, you may notice your bra size goes up and down as you shop across brands. In part this is because this traditional method isn’t really standard. Confusing and frustrating, we know… read on!

Why You Should Get a Professional Fitting 

While these steps probably seem straightforward, there are some complicating factors that make it less easy to rely on this method. 

The biggest issue is that there is no one standard universal sizing. Wearing the wrong bra sizes can cause discomfort, pain and self-consciousness. Different brands, patterns and styles can fit dramatically differently. 

When a professional fitter measures you for a bra, she also takes into account your body and breast shape. Just as different styles of jeans suit and fit our bodies differently, so different styles of bra give different kinds of breasts and bodies better support, shape and comfort.

Try a Virtual Fitting Instead!

The internet has opened up so many exciting shopping options and we all discover new brands we’re excited to try almost weekly! But when it comes to size-sensitive clothing, we can all feel a lot of anxiety shopping from new brands.

Whether you’re buying jeans, shoes or bras, shopping online can feel like a gamble. After all, you have to wait for delivery and if the size is wrong, you’re facing the added hassle of returns. 

Keep it, and the wrong size or fit of bra will ruin your day. You’ll feel uncomfortable, maybe even sore, and just want to get home so you can rip the damn thing off. 

Here are some of the giveaways that your bra is the wrong fit for you:

  • You’re plain uncomfortable
  • You shift around in your cups
  • Your breasts bulge out of your cup or sides
  • The back strap rides up your back
  • Your straps slide off your shoulders, even after you’ve tightened them
  • The underwire hurts your ribcage
  • Your bra leaves painful marks on your skin

At Knix, we really wanted to help more women say goodbye to ill-fitting bras and frustrating shopping experiences. As an online retailer, we know it can be especially daunting to make a bra purchase online. That’s why we developed our virtual fit program. Learn more about it today and book your appointment!

What to Expect from a Virtual Fitting

  • Book your virtual fitting here.
  • We’ll connect you with one of our expert Knix team members for a 1-on-1 fitting session over video chat. 
  • For your bra fitting, we recommend you wear a bra with little or no padding and a fitted t-shirt to make sure we get an accurate measurement. You’ll also need either a) a soft measuring tape or b) a piece of string or cord and a tape measure or ruler.
  • With different styles and sizes for 30A to 42G in the world’s most comfortable and supportive wireless bras, our fit experts can help you get into something that you will love to wear every single day.