How to measure Bust and find a fitting Bra (Answer to “what bra size am I”)

A simple guide to the question - What bra size am I? Learn how to measure bra size and check your bra cup size in the chart given here for perfect bra fitting
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bra fitting guide

What bra size are you – Bra fitting guide

How to determine the size of my bra – this is a question that resonates with all first-time bra wearers. And surprisingly, with most seasoned bra wearers as well.

You can sense this problem by the way breasts bulge in front unattractively or spill out from the sides, the way bra straps sink, cutting into the skin on the shoulders, or the way one looks noticeably uncomfortable wearing ill-fitting bras. Most people buy bras with the band too big and cups too small.

Do not worry or feel embarrassed if you do not know your bra size. You are not alone. 8 out of 10 women in the world do not know. (Maybe not exactly, says this article)

Sometimes it happens that you have fitted yourself with the perfect fitting bra, but with time something has changed in your body, and the bra that fits you is no longer looking right. Even without any weight loss or gain, subtle changes occur in a woman’s body with age. It is a good idea to recheck if you find that the one you have on is not giving you good shape.

It is not just vanity at sake here- your posture, and your future painless back all depends on you fitting yourself a good bra. And you will also be mighty uncomfortable when you are wearing a bra that is too large for your body and cups are drooping in the front.

You do not have to live your life with the wrong bra. Find the perfect one by following the directions given below.

Qualifying properties of a well-fitted bra

FITTING BRA - how it should look

A well-fitted bra serves a very obvious cosmetic purpose. It gives the perfect shape without any unseemly bulges. Other than that, it supports the breasts properly.

If you are well endowed, a well-fitting bra can even alleviate back strain. It prevents the sagging of tissues of the breast.

A good bra is 

  • One that gives real support everywhere, back, sides and front
  • One that will cover the breasts properly ( no bulge  &  rolls above the bra in the front or  near armholes)
  • One that is not too tight that the straps will cut into the skin marking it permanently
  • One that is not too loose that your breasts hang support less.
  • One where all the straps, even the underwire lies flat against the body and the center gore is not twisted.

How to know if you are wearing the right size ?

First of all, determine if your current bra cup fits you properly or not. To do that, you have to take a simple test in front of a full-size mirror. A properly fitting bra should be resting at mid-chest. There should not be any bulges anywhere.

  • Stand in front of the mirror. Find the narrowest part of your body, which is your waist. Mark on the mirror
  • Find your collarbone. Mark on the mirror
  • Look where the fullest part of your breast is at. Mark that too.

Is it in the middle of the top and bottom lines?. If yes, then the bra you are wearing supports you correctly.
If not, it means that the bra is not supporting enough; it maybe time for you to get another well fitted one.

To know if the band size is too loose or not try this-  If the bra band moves freely around the underbust your bra is too loose. If you cannot breathe or if you cannot insert atleast two fingers inside the band it is too tight

Check if you can see bulges or creases instead of a nice round shape in your cup.

Now raise your hands. Is the band horizontal all around you, even in the back? If it is going up in the front or back checkout a new bra size

How to measure bra size How to properly measure for determining the bra size 

A bra size is composed of 2 parts

1. A number which indicates the band of the bra ( 32, 34, 36 etc) .

2. A letter which indicates the cup size (A, B,C).

The measurements you need to know your bra size are full bust and under bust.

(This is US & UK sizes. International size followed by many other countries use centimeters instead of inches as measurement)

bra select - measure the bust
Measure full bust and underbust

What is under bust ?

underbust measurement.

Under bust measurement is the measurement around the rib cage immediately below the bust, where the bust meets the chest. This is a very important measurement needed to know the band size of your bra. 

How to take measurements of bust for a bra fitting

  • Get a soft measuring tape with clear markings
  • Wear a well-supporting bra that is definitely nonpadded. Do not wear any other clothes or minimal clothes on top to ensure accuracy. No pushup bra, please. Underwire is fine. It is better to take the underbust measure by wearing a bra.
  • If possible, get help from a friend. It is better if you have your hands out of the way when taking measurements underbust.
  • If you are alone stand in front of a mirror, to check that the tape is parallel to the ground level.
  • Stand erect and straight when taking the measurement at all times. Do not push your chest out or suck air in. Stay relaxed. 
  • Keep the tape measure straight and level at all times; it should be parallel to the ground when measuring bust and underbust. Ensure it is straight on the back also. It is here that a helper will be of help.
  • The bra you are wearing when you are measuring yourself should be tight enough in the band to get the right measurement. Not too tight that you cannot breathe properly but reasonably and comfortably tight.

Steps for taking bra measurements

Step 1

Measure the bust around the fullest part of the bust, hands at the sides. For most people, this will be across the nipple. Do not pull tight. This measurement is taken slightly relaxed rather than tight. This is a FULL BUST measure. 

When taking measurements round the decimals. If less than 1/2 inch, count down, and if more than 1/2 inch count up. Ie if you measure the bust round as 36.75 take it as 37; if it is 34.25 take it as 34.

Checkout the post on reading a tape measure properly if you do not know how to

Once you have rounded out the measurement if it is an odd number make it the nearest even number ( on the higher side) . ie if you get 37 inches take it as 38 inches

Step 2

Measure the underbust, i.e., around the rib cage just under the bust. Ensure that tape is held reasonably tight without cutting into the skin. Expel all air from your lungs when taking the underbust measurement.

This is UNDERBUST measure. If you get an odd number, round up back to an even number. i.e., If you get 29 inches round to 28 inches. 

Step 3

Determine Bra Band size

You can check out the websites of your favourite brands to see exactly how they consider the band size and cup size. The general method is as follows.  

Add 4 inches to the underbust measure (the rounded figure) ; this is your bra band size .

Ie, if you have a 31-inch underbust measure, you round it to 30 inches and then add 4 inches to this, and you get 34 inches, your bra size.

Determine your Cup Size 

Subtract the underbust measure from the full bust measure; Take this as X.

If X is upto 3 inches. your cup size is A.

If X is 4 inches, your cup size is B.

If X amounts to 5 inches, you should be wearing a C cup, which is the average cup size.

If the X is 6 inches, your cup size is D,

if the X is more than 6 inches it is DD.

Checkout the correct bra size in the table

Bra size chart

chart - underbust and full bust and band size 26 to 29.5 inches
chart - underbust and full bust and band size 30-31.5 inches
chart - underbust and full bust and band size 32 to 33.5 inches
chart - underbust and full bust and band size 34 to 35.5 inches
chart - underbust and full bust and band size 36 to 37.5 inches
chart - underbust and full bust and band size 38 to 39.5 inches
chart - underbust and full bust and band size 40 to 41.5 inches
chart - underbust and full bust and band size 42 to 43.5 inches

chart - underbust and full bust and band size 44 to 45.5 inches


If, after finding your bra size, you decide you need a change in the band size or cup size or find the particular brand you try is not fitting correctly, simply try an alternative size. But do not arbitrarily change the band size or the cup size. Both are connected, so when you change one; the other will have to be changed too.

If the band is too tight, you go up a size in the bra band, and then you will have to go down one size in the cup size.

Tips on Going Bra shopping 

how to measure bra size

Now that you have found the band size and cup size that suits you, it is time to go shopping – Please only buy a bra after trying it. Some stores have a policy of not letting anyone try. At least ask them to let them allow you to try it on top of your clothes. 

Go Bra shopping in simple clothes like a t-shirt so that you can take it off and on with ease. Also, if you have to try it on top of the garment, it helps if you have a single layer of fabric.

Buy a bra that fits just right when hooked on the first set of hooks rather than the last. Anyways the elastic will wear after some time with wear and wash. So getting a bra that hooks rightly only at the last row of hooks is a risk you better not take.

If you are buying online, make sure the store has a return policy.

What are the questions you should ask to get a good bra ?

☝ Is the band too tight ?

☝ Is the cup adequately covering your breast?

☝ Is the cup too pointy ?

☝ Is the center gore gaping ?

☝ Is the underwire ( if it is there) poking into the skin or lying flat in the center?

☝ Is the strap of the bra wide enough to be able to give good support? 

☝ Is it suitable for the outer clothes you wear? Is it visible from the outside ?

☝ Is the strap snugly fitting on the shoulders rather than falling off the shoulders even after adjusting the sliders?

☝ Is the band on line with the underbust even in the back, rather than riding up?  

Realize that every brand of bras available has slight differences in their fit, which is why trying on a bra before buying is a very, very good idea before buying.

Every woman is unique in her body. All of us are made beautiful. No one has a right to make us feel embarrassed of our shape or size. Just get out of any store where you have to deal with prejudice or judgment.

Disclaimer : This is not an exact science. I have found my perfect bra with this table, but yours may vary slightly. Please do take my advice as a direction and go from there. 

Related post : 15 Parts of a Bra – a simple overview of Bra Anatomy ; 45 different types of Bras; 10 criteria to check for when buying a bra.

different types of bra


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Author: Sarina Tariq

Hi, I love sewing, fabric, fashion, embroidery, doing easy DIY projects and then writing about them. Hope you have fun learning from sewguide as much as I do. If you find any mistakes here, please point it out in the comments.

5 thoughts on “How to measure Bust and find a fitting Bra (Answer to “what bra size am I”)”

    • Hi Anne
      Maybe you have what is termed as shallow breasts – I have read that plunge bras / demi cup bras are better suited for this shape. If you find a size that fits the front/cups you can maybe use an extended for the band, if that makes sense. You can search for best bras for shallow breasts and do a lot of bra shopping in person 🙂 best wishes

  1. What if your bust is uneven (one larger than the other)?

    Front closing (usually sports) bras –often “racerback” –are great for older women with arthritis, or those who just hate the idea of fastening a bra in front and then sliding the fastening to the back, which is poor design.
    Say something about these? Some catches are “dependable” (bikini clasps) and others are undependable –with fastening hooks that can slip.

    The USA offers some good- looking front closing bras that give great support. But I am in the UK where apparently they haven’t thought of the idea. I can’t understand this!

    • Hi Petrichor,
      Nice thoughts. For uneven breasts you can buy removable inserts and use just on one side ; and for padded bras, wouldn’t the rounded shape solve the problem? or just remove the pad from the smaller side.

  2. What a great article. My bras are very uncomfortable. I’m going to use these tips and buy a bra that feels better. Thank you!

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