How to Measure Your Bra Size

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As a woman, I’m no stranger to how frustrating sizing for clothing can be, more so when it comes to underwear.

Figuring out how to buy a bra that fits, especially if my bodies have just gone through some changes, is only one reason why so many women are wearing the wrong bra size every day.

Whether you’ve lost or gained weight, prefer different brands, or feel like you’ve never worn the right bra size, learning how to measure a bra size can be the key to finally wearing a bra that not only fits well but also makes you look and feel good.

A woman wearing a pink push-up bra with strings and black leggings is seated on the bed

How to Measure a Bra Size

For the most straightforward way to measure bra size, you need a soft measuring tape so you can get the exact size of your chest area. Use the measuring tape to measure your bust and underbust in different positions, like standing, laying down, or leaning forward.

It’s best to do this while you’re not wearing anything (even a bra) to get the most accurate measurements. The measuring tape should be very snug.

If you don’t get a whole number, round it to the nearest one. If what you get is an even number, you need to add four inches so you’ll have room to move around.

Steps in Measuring Bra Size

Step 1Use a tape measure to measure under the breasts and around the back
Step 2If you get an odd number, round up the number to the nearest inch
Step 3Measure the fullest area of your breasts
Step 4Subtract the band size from the chest size
Step 5The number that you get is your bra’s cup size. For example, 2 = B cup
Step 6Combine the measurements of the band and cup size. It should have a number followed by a letter, like 36B
Step 7To know if the bra strap is right, you should be able to slide a finger underneath

Factors to Consider While Measuring Bra Size

Once you have your measurements written down, you can enter these measurements in a bra size calculator and it will save you a lot of time, effort, and struggle when you go shopping.

That way, you can easily browse through bras in retail stores since you already know what you are looking for. 

However, aside from your bust size, many factors determine bra size that you need to consider if you want to get an accurate measurement and be confident that you’re wearing the right size. 

Band Size

The bra band is the band that can be seen on the front part, below, and around the bra cups. It is elastic, so it adjusts when there are changes in your body, like when you lose or gain weight. 

Stand upright and use the tape to measure under your breasts and around your back. Make sure that the tape is steady and it forms a straight line. It should not be too tight as you need space to breathe. 

A woman looking in the mirror wearing a black push-up bra and black leggings

Make sure that you measure the bra band in inches. If you get an even number as a result, then that is the band size of your bra. However, if you get an odd number, you need to round up the number to the nearest inch. 

Cup Size

Your bra’s cup size is the difference between your bust line and your band size measurement. Before proceeding to get your cup size, it is highly recommended that you have your most comfortable bra on so that your breasts are positioned in the right place. 

Once you have your favorite bra on, measure the area of your breast that is the fullest. Next, subtract the band size from the chest size. The number that you get is your bra’s cup size and it should look like the following:

  • 0 = AA
  • 1 = A
  • 2 = B
  • 3 = C
  • 4 = D
  • 5 = DD
  • 6 = F
  • 7 = FF and so on

Combine the measurement of your bra band and your cup size, and you should have a number followed by a letter, like 34F. This will be your cup size measurement. I have created a very handy bra size chart that you can use as well.

However, it is important to keep in mind that aside from getting the numbers, you also need to consider the style, the fabric used, and the overall fit. 

Bra Straps

If you’ve got your cup size and band size written down, there is another factor that you need to check, and that is the bra strap. To know if the bra strap is right, you should be able to slide a finger underneath it but it should be tight enough that you can’t lift it. 

The bra straps should also be easily adjustable and should not leave a mark on your skin. If you find yourself adjusting the straps often to lift your chest, then you need to measure your band size again. 

If the straps slide off your shoulders when you move, you need to change the band size to a smaller one. It is highly recommended that you measure the bra band every six months so you can make the necessary adjustments. 

A back view of a black plunge bra with underwire and adjustable straps held by a woman

The Importance of Having a Well Fitted Bra

Aside from having a comfortable bra to wear daily, having a well-fitted bra can bring you health benefits. When you wear the wrong bra size, you can suffer from pain in your back, your neck, and your shoulders. 

If your bra does not fit you well, it can cause several issues. You may suffer from body pain, poor posture, or sagging breasts.

The skin on your breasts and around the chest area is delicate, and with the wrong fit, that area could get irritated. A bra that is too tight can cause redness and patches and it could trap sweat that causes body odor. 

Related Questions

How Will I Know if I’m Wearing the Wrong Bra Size?

You’ll know you have the wrong bra size if there’s wrinkling in the cups, an underwire poking on your sides, and a band that rides up. In some cases, you may encounter cup spillage, slipping straps, or bra marks.

What if I Fit In Two Bra Sizes?

It’s normal to fit in two bra sizes because your actual bra size has two sister sizes. For example, if you have a 34C bra size, you can size down to 32D or size up to 36B.

How Should I Choose a Bra for My Size?

When choosing a bra for your size, you must consider the appropriate cup style for your breast shape and the level of support you need. You may pick contouring cups or wired bands for lift, depending on your needs.

Bra Size Measurement & Cup Size | A, B, C, D, DD Bra Sizes AND Extra Large Breasts


Learning how to measure your bra size has a lot of benefits. It makes you feel more comfortable, it gives you the right support, it prevents you from having body pains and it prevents your skin from getting irritated. 

When you know how to measure your bra size, it can save you from getting the wrong one. It will also save you time in searching for the ideal bra for you. 


Allena is the Founder and Editor of The Better Fit, a platform dedicated to empowering women with practical advice on bras and fitness, inspired by her own revelation of the widespread issue of incorrect bra sizing. Her expertise and tips have been recognized by major publications such as Cosmopolitan, Better Homes & Gardens, Insider, and NBC, making her a trusted voice in women's wellness and lifestyle.