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Calculate your Ideal Bra Size Step by Step

Have you ever had the feeling that your bra is squeezing you or that your breasts seem to be escaping from somewhere? If so, you are not alone. Many women wear the wrong bra size without even realizing it, which can cause discomfort, pain, and even long-term health problems.

But don't worry, because in this article we will show you how to calculate the ideal size for your bra. So get ready to say goodbye to ill-fitting bras!

Why is it important to calculate the size correctly?

Calculating the correct bra size is crucial to ensure proper comfort and support for your breasts. If you wear a bra that doesn't fit properly, you can experience a number of complications, including neck and back pain , chafing, skin irritation, or even long-term posture problems.

Also, wearing a bra that is not your size negatively affects the shape and appearance of your breasts, which can lower your self-esteem and confidence. Therefore, taking the time to calculate the ideal size is essential if you want to feel comfortable and confident in your underwear.

What is the difference between ABCD cup?

The bra cups “A, B, C, D…” represent different cup sizes , with A being the smallest and F being the largest. The difference between each of these cups lies between the circumference of the bust and the circumference of the bra band.

The bra measurement is taken under the bust, while the bust measurement is taken at the fullest part of the bust. The letter of the cup is determined by the difference between these two measurements.

In general, cup A is the smallest and usually corresponds to a difference of 2 cm between measurements. Cup B corresponds to a difference of 5 cm, cup C to a difference of 7 cm and cup D to a difference of 10 cm.

It's important to note that bra brands can vary slightly in cup shape and size, so one brand may have a different cup size than another . Additionally, cup size can also vary by bra style, as some styles may have more or less coverage than others.

How to know what type of cup you are?

The first thing you should do is go to your closet and find your best bra , preferably one without push-up or padding. Then write down the size and once you have it on, start measuring yourself and compare the measurements with the bra size. If it fits perfectly, then you chose the correct size.

On the other hand, once you have these measurements, you can use a bra size chart to determine your cup size . Cup size is determined by subtracting the band measurement from the bust measurement and comparing the result to a size chart. For example, if your band measurement is 86 cm and your bust measurement is 96 cm, the difference is 10 cm. What corresponds to an A cup.

Remember , bra sizes can vary between brands and styles, so you may need to try several sizes and styles before you find the best fit.


Difference Cup
10-12 TO
12-15 B.
15-18 C.
18-21 D.
21-24 AND
24-27 F



Do it this way step by step

Before you begin, you should know that bra sizes are made up of two fundamental values, known as cup and size. When we talk about size we refer to numbers as (80, 90, 100...) and when we talk about cup we refer to the letter (A, B, C, D, E...).

With that said, let's get started!

Step 1: Calculate the size

Measure the contour under your chest with a tape measure. It is important that the tape is completely firm, but not tight. Then add 15 cm to the number you marked.

Your size will correspond to the rounded figure that is closest to the number obtained.

For example: 74 cm + 15 = 89 cm. The ideal size would then be 90.

Step 2: Measure at the height of the nipple

Now, it's time to calculate what the letter of your bra is . When we talk about the letter, we mean the volume of the chest in relation to the contour. The letters are classified from A, which is the smallest chest, to F, which would be the largest chest, which means that the further away the letter is, the more volume the chest has.

Step 3: Subtract to get the letter

The cm that you obtain in step 2, you must subtract them with the figure obtained in step 1, but you must do it before adding the 15 cm. Once the subtraction is done, you should look at the equivalence table to finally establish what the letter is.

For example: 89 cm - 74 cm = 15. The result corresponds to a B cup.

Size guide

Take a look at the following tables and find out quickly and easily which is the right size for you.

Chest Up to 81-86cm 87-92cm 93-98cm 99-104cm
under chest Up to 66-71cm 72-77cm 78-83cm 84-89cm
Size 80A 90A 95B 100B
80B 90B 95C 100CD
90 CD 105CD
S m L XL


Benefits of wearing the correct size

Wearing the correct bra size can have several benefits for health, comfort, and appearance. Here we present some of them:

  • Wearing the correct size can offer you great comfort, plus it will prevent the bra from shifting and making you feel uncomfortable during the day.
  • The right bra will give you the ideal support for your breasts, which can help reduce back pain and improve your posture. If you wear the correct size, your shoulders won't be rounded and your back will stay straight thanks to the support your chest will receive.
  • It can improve the appearance of the bust and overall figure, which can boost confidence and self-esteem.
  • Wearing the wrong bra size can cause health problems such as neck and back pain, skin irritation, and respiratory problems.
  • By wearing the correct size, you will reduce stress on your bra and prevent it from stretching or becoming misshapen over time, which can extend its lifespan.
  • The ideal size immobilizes the chest and prevents rupture and loss of flexibility in the Cooper ligaments, in addition, it also prevents its fall.
  • The bra that provides you with enough support while you exercise will allow you to enjoy your routine, since if it were too loose or too tight, it would cause you discomfort.
  • That's why it's so important that you take the time to find the right size, as this way you can make sure the bra fits perfectly and gives you better support.

    Clotsy Brand Bras

    Are you looking for comfortable and also sustainable bras? Then you are in the right place, because our new collection of bras will do your breasts and your health a favor, offering you great comfort and less pain.

    On the other hand, since we always bet on sustainable fashion , our bras are made with 100% sustainable materials, which means that they are not made with toxic chemical components that can cause itchy skin . As they are sustainable women's clothing made with natural fibers such as organic cotton , these garments respect 100% the slow fashion production process.

    Don't think twice and get the best bras from Clotsy Brand ! If you opt for them you will have a sustainable lifestyle ! If you are interested in dressing with clothes and accessories that respect the environment, we invite you to visit the vegan clothing categories on the web.



    It is important to select the correct size, since a wrong choice can significantly affect the comfort , support and health of the breasts and back. A bra that is too small can cause pain and pressure on the breasts, as well as the back, while one that is too big may not provide adequate support and cause the breasts to shift uncomfortably.

    By wearing just the size you need, you can improve your posture and the appearance of your bust, which in turn can boost your confidence and self-esteem.

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    Author: Clotsy Brand Team

    Clotsy Brand is made up of a team of committed people with the caring for the planet and ethical fashion production. All Clotsy garments are produced in local workshops in Spain and Portugal, using sustainable materials that take care of both the planet and the skin of their customers. We value the opinion of our community, so we are always close to them and willing to listen to their ideas and opinions through different channels, such as Instagram, Telegram, Email and Tiktok.


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