How to Measure for a Bra

bra size measuring

Most common measurement method for bra sizing

Proper bra measurement is crucial in ensuring that you have the best-fitting undergarments. Too many women spend money on purchasing well-fitting clothes but spend less attention and time on what they wear under them. Bras that are too small can cause back pains and shoulder aches, and bras that are too large will not provide enough support.

Measuring for Bra Size

There are a couple ways to measure your band size, but the most common is to measure under the bust to determine the band size, then to measure across the fullest part of the bust to calculate the cup size.

Measuring Under the Bust

Underbust +0: Place the measuring tape directly under your bust, parallel with the ground. Breathe normally, and measure after you’ve exhaled. Take your band size in inches, and round to the nearest even number. This is considered the most modern and effective way to measure for a well-fitting bra.

Determining Bra Cup Size

To measure your cup size, measure your bust at the fullest part of your bust, making sure that the measuring tape is parallel with the ground. Measuring your cup size is a little trickier because the size of your breasts can change depending on many factors, including bloating; pick a day where your they feel relatively true-to-size, or average out the measurements across different days.

Your cup size is proportional to band size, which means that your cup size is actually the difference (in inches) between your band size and the fullest part of your bust. 1” is an A cup, and each additional inch increases the cup size alphabetically.

Inch to Bra Cup Size Conversion

0 inch AA cup
1 inch A cup
2 inch B cup
3 inch C cup
4 inch D cup
5 inch DD cup
6 inch DDD cup, or F cup
7 inch G cup

Use the difference in inches between your band size and the fullest part of the bust.

Alternate Bra Measurement Method – Above the Bust

measure for bra size

Over-bust measurement method

Above the bust: Place the measuring tape directly over the bust (under the armpits). Breathe normally, and measure after you’ve exhaled. Take the measurement in inches, and round to the nearest even number. This method is used primarily by Victoria’s Secret. However, this method has been mentioned as a way to artificially add inches to the band size, compromising support. It has also been described as a way to “fit more women into fewer sizes.”

How to tell if It’s the Right Fit

Snug: the band should be snug, but not too tight. It is the band that mostly supports your breasts, not the straps. You should be able to put no more than 2 fingers under your band. If it’s too tight, go up one band size at a time; if too loose, go down.

Smooth: It should be lying straight across your back. If the bra is too small, it will squeeze the flesh on your back and front, making unsightly bulges. If your bra rides up, it’s too loose and you should go down a band size; if it cuts into your flesh, it’s too small and you should go up a band size.

bra size

Properly fitting bra

Cups should contain you: your breasts should not bulge outside your cups either in the front or to the side under your armpits. You can assess side coverage with the underwire in an underwire bra – it is correct if the end is pointing towards the middle of your armpit. If it’s too small, it will dig into your flesh and hurt, and you should size up a cup size.

Alignment:  The “gore” — the center of the bra, often where the underwires meet — should touch the sternum. When the gore is at the sternum, it makes for the best fit.

Sister Sizes

To correct for the variance in manufacturers’ sizing, “sister sizing” is a quick way to find a bra with a better fit. Sister sizes are the sizes that surround your current bra size.

To go down a sister size: reduce your band size by 2, but take your cup size up by one (e.g. 36C’s sister size is a 34D)

To go up a sister size: increase your band size by 2, but go down one cup size (e.g. 36C’s sister size is a 38B)

Outdated Measurement Method

If someone has ever told you to measure under your bust and then add four or five inches to get your band size, you may have been confused. This method was used in years past and is considered an outdated fitting method, leftover from a previous measurement system where your measurement from the fullest part of your bust correlated to your band size. Band sizes is now based solely on your underbust measurement.

Finding the Best Bra Fit

In sum, measuring for a well-fitting bra is not as difficult as it may seem, but the results will provide a lot more comfort to your everyday life. If ever in doubt, visit a bra measurement specialist to get yourself professionally fitted. Lingerie departments in most major department stores and specialty lingerie boutiques usually have a professional bra fitter on staff to assist you.

29 thoughts on “How to Measure for a Bra

  1. Thank you for clarifying all of the conflicting information on correct bra size measuring! I was ready to burn them all! Ha ha

  2. Hi. Unfortunately, these instructions are missing a very important piece of information in calculating the Cup Size – determining the “Band Size”. The Band Size is not the same thing as the underbust measurement. It’s either 4″ or 5″ longer.
    To determine cup size, measure the underbust and add 4″ if the underbust is an even number, or add 5″ if the underbust is an odd number, to determine the Band Size. To get the Cup Size, subtract the Band Size from the overbust (measurement of the fullest part of the bust). The difference (in inches) is your Cup Size, as shown in your table: 1″ = A, 2″ = B, and so on.
    If someone were to use the current instructions listed here, they would think they’re a G cup when they’re actually a B cup. Big difference!
    I like the rest of this site, this is why I’m taking the time to let you know of the missing 4″ or 5″. I hope this helps. Thanks.

  3. Hi CJ,

    Actually, while your comment was correct in older / traditional measurements for bras, most modern bra companies are now using one of the 2 methods we describe above. The change that happened a while back is part of why this issue is so confusing for everyone, but we contacted a lot of lingerie companies and almost all of them now use the 2 methods above. We are glad you like the site!!!

  4. Thank you for the response.

    To be clear, a person who is currently a 36C is now a 32H? 40″ overbust – 32″ underbust = 8″ or 32H. I did some research and trying to find a 32H is very difficult, where a 36C is available just about everywhere. I guess there’s still a lot of stores that haven’t caught up with the new sizing.

    Maybe a footnote or something with the old sizing could be helpful to those still wondering if that really cute bra they saw that’s only offered from sizes 32A to 40D would fit them. Thanks!

  5. Funny in an odd sort of way, but as a very large breasted woman I completely understand the discourse between these two measurement style.

    Actually, my personal experience in that you are both correct. My measurement is 31.5 inches underbust and an overly abundant 37.5 overbust. I can assure you it’s difficult finding a properly fitted brassiere.

    In support of this article’s recommended method for measuring I can honestly attest to the fact that such a method is the better of the two. I know this because for years and years the best bras I’ve ever had we’re from a specialty shop that is now closed. To my own sense of agast, I indeed I measured as a size 32GG. Those bras were expensive, yet well worth every cent they cost. Because they were both the best fitting and prettiest bras I have ever had. Unfortunately, like everything else my bras wore out and I needed new ones. Regrettably my Atlanta specialty lingerie store is now closed, as it did not survive the recession.

    Here’s were the “old method” comes into play. It is somply my best current recourse, as I’m currently not living in an environment that has specialty lingerie shops. Thus, while in this rural environment I’m in the same mode as everyone else trying to find a bra in your typical department stores that will fit.

    Frankly, for the most part that is a futile effort. I now wear, with great discomfort I might add, sister sizes because it is the only choice available to large breast rurally located women …36DDD whenever I can find them, or a worst, a 38DD.

    Needless to say, these are poor substitutes for a properly fitted bra. However, they are the best I can do, short of a specialty lingerie shop. I will readily admit that despite so doing is a bit embarrassing, I often find myself squirming and pull on the sides of my bra in an effort to find some degree of comfort.

    The good news for me is the continueous discomfort tipped the scales in long thought out decision. Thus, I’m going to have a breast reduction. Although, I don’t necessarily relish the pain of surgery in the long run it is the better choice for my health. Especially, as I firmly believe having small breast will grearly help to reduce the amount of pain I suffer in my neck and shoulders.

    Then as an extra bene, I will not have such horrible bra fitting problem ever again.

    In summary, both of you are correct. The article’s “new method” will most likely yield the best fit. Especially for harder to fit mega sized breast. However, there still exist a great deal of practicality in the “old method.” As many women can neither afford, or even have available sources for, the bras from retailers utilizing the “new fitting” method. Although they would probably find a way to afford the better (and much more comfortable) fitted bras, saddly such product choices are not yet the most widely available ones for the many, many women.

    1. My gosh, sure should have edited before pressing the comment button. Readers please forgive and mm over look my typing errors. Haha, because, yes, I do understand the proper use of English grammer, but I am certainly not so very good as a typist.

  6. I also have experience being a larger cup, I am currently a 32F, having just lost weight and coming down from being a 32G. Before I was fitted in a proper lingerie store, I was using the more traditional method of bra fitting. Having tried both I can say that using the modern way of fitting where under its measurement equals band size, I have gotten a much better fit with way better support resulting in a minimizing effect, better lift and less back pain. Using the other method however, things just didn’t fit right, made me look larger, and hurt my back and self esteem. Even if these larger cup sizes are difficult to find, it’s worth the effort. Why settle for something that does not fit just because it’s easier. I have small feet too, size 5.5. Should I wear shoes that are too big just because my size is less abundant?

  7. I thought I might add too: if women stopped settling for ill fitting bras, maybe more companies would be forced to start making those hard to find sizes.

  8. Lets say you get 32 inches and round it up to 36, when measuring cup size do you subtract the final number, 36, or the number 32?

    1. Hi Lynzey,

      If you measure at 32 inches, you wouldn’t round it – you would use 32 since it is an even number. So, you’d subtract using 32 when calculating cup size. Good luck!

  9. I measured my band at 35 and my bust at 42. I’ve been wearing a 38DD bra from a plus-size clothing company that has fit me quite well and is just recently becoming too tight in the cups. Any thoughts for me? Do I really need to start looking for 36G bras…?

    1. Hi Lisa,
      There tends to be a lot of leeway in band sizing because many bras have some adjustments/different hooks. This is why you’ve been successful with a 38, but yes, you may be happier in a 36. Also, when you go to a larger band size, it can give you some extra room in the cup, even though it is doing so without ideal fit. Also, keep in mind different brands and cuts are going to have slightly different fits so your size may vary, for example in a demi cup vs. one with full coverage.

      It does sound like going up a cup size and down a band size would be your ideal for most brands. In some brands, that cup is called a G, but many use DDD instead, so make sure to look for that as an option!

  10. I just bought a 40 DD. the band of the bra measures 34 inches. How does that fit my 40 inch underbust? It’t way too tight. I want the band to fit, then go for cup. I don’t understand.

    1. HI Sharon,

      It sounds like either your bra was mis-marked with regard to the size or that the brand is not following standards. I would suggest returning it and trying a different brand.

    1. It is recommend every couple of years unless you’ve had a weight change or other fluctuation such as you changed workout habits, put on more muscle etc.

  11. My band is 33.5 (do I round up or down?) My bust is 39. According to the classic method I am a 34DD. I also tried it according to a clarifying comment- in which case I’d be a 34A. Both seem wildly off. I currently wear a 36B (per Vicki’s Secret I had them measure it- the process here for them seems too complicated). I am at a loss for my size.
    I also feel that women’s sizing should be more standardized in general. It would help body positivity to look at things objectively- by measurements, instead of sizes. I am sort of angry at the women’s clothing industry in general.

  12. I’ve been wearing 36DDD for years and am considering breast reduction to alleviate neck/shoulder pain.
    My underbust measurement is 30 & overbust is 38 which would be 30H in a more expensive or modern measured bra. If I get surgery I’m going down to C cup or maybe B
    Please help me with the bra size I may need if approved for the surgery?

    1. There are many factors that could affect your bra size at this time. I would wait until after your surgery to properly measure for your new bra size.

  13. My underbust measures 38” and my overbust is 42” could you please tell me what size bra I should be wearing.

  14. My under bust (rip cage) is 30
    My fullest part of breast is between 34-35
    What would my size be?
    I’ve been wearing a 32b but feels too small now so was told I’m a 32D which is too big I’ve brought a 34c bra but there are slight gaps at the top of the bra so I’m quite confused as to what size I am 😐

    1. Since you are having a tough time finding a bra that fits and is also comfortable, I would suggest visiting a bra measurement specialist to get yourself professionally fitted. Lingerie departments in most major department stores and specialty lingerie boutiques usually have a professional bra fitter on staff to assist you.

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