Bra Fitting 101

posted in fitbra

I can't tell you how many woman come into our shop wearing the wrong size bra, it's practically an epidemic. Bands too big, cups too small, you name it we've seen it. Figuring out your proper size is crucial to ensure you're getting enough support, lift, contouring, and the right silhouette from your bra. At the shop we provide personal fittings, but for those of you who can't make it in we offer this online tutorial. Our goal is to see every woman wearing the correct size so that she looks great and feels her best.

First let's take a look at a diagram labeling your Chest, Bust, and Underbust. We all need to understand and speak the same lingo before we can move on. Your Chest measurement is taken above your breasts, your Bust measurement is taken at the fullest part of the breasts, and the Underbust measurement is taken around your rib cage just below your breasts. These three measurements together will produce the magic formula to decode your illusive bra size.

Bust Measurement Diagram

Bra sizing is all about proportion. The ratio of Underbust and chest to your Bust measurement is the basis of size. The Chest and Underbust measurements determine the band size while the Bust measurement determines the cup size. Cup size is dependent on the amount of projection and volume of the breast in comparison to your Chest and Underbust. To determine what band and cup you should be wearing you will first need to measure these three components. For some women, your band size will be closer to your Chest measurement. For others, the Underbust measurement is the key number, and all of the above is relative to how your body is shaped and what brand you choose to wear. Confused yet?? Keep reading and we'll try to unravel the mystery.

It's All About the Volume

Because of the many ways bras are designed and constructed, variation in size will occur, so the first thing to realize is that all of the information here is intended to guide you, rather than it being carved in stone, especially when comparing one brand to the next. If you normally fit a 34B you may also fit a 32C, a 30DD, or a 36A. This is because all of the sizes just noted utilize the same size underwire. Going up a cup and down a band size alters the proportion of a bra, but generally doesn't change the volume of the cup. Shifting up or down this way when trying on sizes can help you find your perfect fit. See the chart below showing equivalent bra sizes, and realize that as you move across the chart, each of the bras on the same color line share the same size underwire and similar cup volume. Understanding the issue of cup volume is the key to decoding bra fitting.

In the chart below follow the lines across by color to see equivalent bra sizes. We most often find that women are wearing their band size too large, and their cup size too small. The result is that your bra is not only lacking in support, but is also likely flattening you out and not giving you the perky, youthful shape you want from your bra!

Bra Size Chart

Now take this quick test; stand in front of a mirror with your arms at your sides, wearing your regular everyday bra - is the height of your bust below the middle of your upper arm? Do your breasts seem to be floating off the side of your torso somewhere near your elbow? If the answer is yes, you are suffering from a droopy silhouette and the wrong bra! Both are completely avoidable fashion faux pas.

Take a further look at the bra you're wearing now and ask the following questions;

-is the band too tight?
-is the band too loose?
-does it sit straight and low across your back or is it riding up?
-does it fit smoothly across your sternum with the center gore flush against the breast bone?
-are the cups baggy or rippling?
-are your breasts spilling out the top, center, or sides of the cups?
-is the underwire digging in at the center or sides of your breasts?
-are your straps digging into your shoulders?
-are your straps falling off your shoulders?

Now that you've looked at your current bra fit with a critical eye, it's time to take action!


Get a tape measure and measure your Chest, Bust and Underbust. Everybody should own one, but if you don't, here's a Printable Tape Measure. Reference our diagram up top to make sure you know where to place the tape. Hold the tape firmly and snugly, but don't pull too tight. Be honest! Write your measurements down and get ready to start calculating.

If your Chest, Bust, and Underbust are all within three inches of each other proceed to Method A. If any of your measurements are greater than three inches different from each other proceed to Method B. We found that one hard and fast rule does not make for the best fit experience, so have distinguished two methods to streamline and simplify, based on figure type.

Method A - For Most A/B/C Cups

Band Size

The smaller your breasts, the more likely it will be that your Chest measurement is the closest indicator of your band size. If your Chest measurement is an odd number, add one inch, since all band sizes are in even numbers, 32, 34, 36, etc. This number is your band size.

Cup Size

Bust (-) Chest = Cup Size

How many inches of difference are there between the two numbers? Each inch equals a cup size.

Use the chart above to see which other sizes may fit. If your rib cage is narrow try going down a band and up a cup, and see Method B. If you have a broader Chest go up a band and down a cup. See how the correlating sizes feel to determine which size is right for you in a particular brand.

Method B - For Most D Cups and Above

Band Size

The bigger your breast the more likely that your underbust measurement is the closest indicator for your band size.

Cup Size

Bust (-) Underbust = Cup Size

To determine your cup subtract your Underbust from your bust measurement, each inch is equal to a full cup size.

The Curvaceous Figure

Here is an example of a very common set of measurements for a curvaceous figure; Chest 35, Bust 39, Underbust 34.

We frequently see a woman of this shape wearing a 36D bra, when there is a high likelihood that she would get better support, lift, and shaping from a 34DD.

Use the chart above to look at equivalent sizes. Be sure to experiment with going down a band size and up a cup size and vice-versa. Different brands fit differently and it is important to try a variety of sizes to determine which is best for you.

Now that you're armed with information, it's time to take those numbers and hit the fitting room at your favorite local lingerie boutique or department store.

IMPORTANT - ALWAYS ADJUST YOUR STRAPS! Most women fail miserably in this task. When you do get into that fitting room, make sure you adjust the shoulder strap to the loosest setting BEFORE you put the bra on. Once the band is secure, on the tightest setting that is snug and comfortable, sitting straight and low across your back, THEN and only then, adjust the shoulder strap.


Now that the bra is on you, if it doesn't immediately seem to be a complete disaster, check the following;

Band Size Too Big: if you can pull the band away from your back more than 2 inches your band size is too big. Stop. Go back to your calculations and start again. The likelihood is that you will go down a band size and up a cup size. Many women who fall into the average and small category are wearing enormous bands, that are ridiculously loose, but complain that the correct fitting size is too tight. You shouldn't be strangled, but if you can fit a small child in between you and your bra band, it's too big! Ease into your correct size. If the numbers say you should be two band sizes smaller, start by going down one band size, get used to the feel. Start noticing that your clothes look better on you and that your silhouette is shapelier...

Band Size Too Small: if the band is truly uncomfortably tight, go up one band size.

Band Size Too Small: if the band feels snug and secure and the cups seem ok but the center bridge is sitting more than 2 inches away from your chest wall keep the same band but go up a cup size. This will likely only occur for women with a DD or larger cup size. Manufacturers allow 1.5 inches of tolerance as the acceptable amount of distance between the chest wall and bridge of your bra. If your bra has a slight gap at the center but fits well in all other ways this is an acceptable variance. You're in the right size.

Cup Too Small: if your breasts are spilling over the top or center of the cup, but not at the sides, stay in the same band size and go up a cup.

Cup Too Small: the wire is not encasing the breast around the outside edge but seems to fit everywhere else, first try going up one band size. Though the band you are wearing may not feel too tight, we recommend you go up a band and down a cup. You will be wearing a bra with the same wire only with a slightly wider distance between the cups.

Cup Too Big: if the cloth of the cup is rippling, or there is a gap between the molded cup and the top of the breast, go down one cup size. You may want to try going down a band and a cup.

Cup Fits but Wire Is Digging In: If the breast is encased in the cup, but the wire is digging into your arm pit, go down a band and up a cup. This should put the wires closer together and eliminate any irritation under the arm.

Now that you're armed with information, we hope you'll put it to good use! Allow yourself at least an hour when you decide to go bra shopping, and if you're shy, try to get past it and let the fitting ladies help you, wherever you decide to buy your bra. We all really do want to see you succeed!