Four Ways of Measuring

Four Ways of Measuring

How exactly do you measure to determine a bra size? There are four ways of measuring that I know of and each one has its merits and pitfalls. Let’s go through them one by one.
Method 1 – Rib Cage and Full Bust
This is the method used by bra fitters in retail stores everywhere. In fact, almost every website tells you to use this method to determine your bra size. Take your rib cage measurement directly under the bust. Add 4 or 5″ (some websites say to add 6″) to determine your band size. So if my rib cage measures to an even number such as 32″, I would add 4″ to obtain a band size of 36. Or according to some websites adding 6″ would result in my band size being 38. If my rib cage is an odd number such as 33, I would add 5″ for a band size of 38. 

Then, measure the full bust – that is the fullest part of the bustwithout compressing the breast tissue. Let’s say that is 40″. I then subtract the band size from the full bust measurement and I should come up with my cup size. So 36 from 40 is 4″. Each cup size is equal to 1″ so A=1″, B=2″, C=3″ and D=4″. If my band size is 36, then I would be a D cup. However if I used my band size as being 38, then my cup size would be B. So you can see where this method has a big downfall.

Understand that these measurements do not always tell the whole story. if a woman has a very small rib cage or a very wide back, these measurements will skew the bra size to appear larger or smaller than they actually are. 

 

Method 2 – High Bust and Full Bust

This is the method recommend in my bra patterns where someone has only a tape measure and a mirror (and not their Fairy Bra Mother!) at their disposal. This method of determining bra size works very well for most women I use the High Bust Measurement (above the bust but still under the arms), and add NOTHING to determine the band size. After measuring over 10,000 women, I still find I am far more accurate measuring the high bust rather than the rib cage. I simply round up or down the high bust measurement to the nearest even number.  So in my case, I measure 36″ on the high bust, so my band size would be 36. A 35.5” high bust measurement would also indicate a 36 band.
 
 
I still measure the full bust, but I subtract the high bust from the full bust, with 1” of difference equaling A cup, B cup is 2”, 3” is C cup and so on. My full bust is 40″ so my bra size would be 36D with this method.
 
 
But once again, there are always some for whom the measurements don’t tell the full story. if a woman has a very small rib cage or an athletic build, the high bust measurement can be skewed a little. 
 

Method 3 – Bottom Cup Depth

I have a third way of measuring – in fact, it is a very accurate and sure-fire way of measuring, but the downside is that you have to have a bra that already fits to do this. First measure the high bust to determine the band size. Remember that is over the bust, but under the arms. 
 
 
This method for sizing uses the Bottom Cup Depth. The Bottom Cup Depth determines the overall volume of the bra cup. No other measurement is as important as this one. This is the distance from the bra bust point to the bra wire line measured on the true vertical. You must wear a well-fitting bra in order to take this measurement.
 
 
In a perfect world, the bottom cup depth on your bra should measure the same as the bottom cup depth on your naked breast, but it often doesn’t – because of the breast density and degree of flaccidity.The nipple will drift downward as the breast loses its self-supporting ability, which means that even if your bra size does not change over the years, your BCD will still decrease as you age. Nothing stops gravity.  So it is imperative to wear a bra that fits (not a foam lined bra, or a sports bra either). The bra is actually placing the nipple in the ideal location.
The Bottom Cup Depth (BCD) increases by 1/4” (6 mm) per size in not only my patterns and other commercial bra patterns, but as an industry standard.
Using the chart below, find the BCD in inches that corresponds to your own Bottom Cup Depth (measuring the bra from the nipple to the wire line directly below it. On each line, you will find the Pin-up Girls bra pattern sizes that correspond with that BCD. Just use the band size along the line that equals your high bust measurement. For me, that is 4″ BCD and 36″ high bust, so 36D
BC depth
Bra Sizes that use this BCD
2.25
30A
32AA
34AAA
2.50
30B
32A
34AA 
36AAA 
2.75
30C
32B
34A
36AA
38AAA
3.00
32C
34B
36A
38AA
3.25
30D
34C
36B
38A
3.50
32D
36C
38B
40A
3.75
30E
34D
38C
40B
42A
4.00
32E
36D
40C
42B
44A
4.25
30F 
34E
38D
42C
44B
46A
4.50
32F
36E
40D 
44C
48A
4.75
30G
34F
38E
42D
46C
48B
5.0
32G
36F
40E
44D
48C
5.25
30H
34G
38F
42E
46D
5.5
32H
36G
40F
44E
48D
5.75
34H
38G
42F
46E
6.0
36H
40G
44F
48E
6.25
38H
42G
46F
6.5
40H
44G
48F
6.75
42H
46G
7.0
44H
48G
7.25
46H
7.5
48H
 
Do not be discouraged if your ready-to-wear bra size and your bra pattern size are not the same. If the Bottom Cup depth is the same, the cup will fit the same way.
If you are using another bra pattern other than mine (and really…how could you?), check the BCD on your ready-to-wear bra against the pattern that you have. Make sure you are measuring between the seam lines, and not to the outer cutting line of the pattern.  If the Bottom Cup Depth of the bra pattern is the same as yours, you are in business!
 
 
Method 4 – Sample Bras
The fourth and final method is the method I use in all my classes. This is the most accurate method of measuring but it is only used by custom bra-makers and of course bra-making teachers (myself included). I have a set of sample bras in every BCD size. Once you get used to guesstimating the size of the breasts, you can quickly put a woman in a bra size that fits. My rule is to use the bra size that fits the best with the least alteration.
 
So there you have it – four ways of measuring to determine bra size. Which method do you use and have you tried these others? I want to hear from you!
 
53 replies
  1. Karey
    Karey says:

    I never had a bra that fit well until I went to a specialist bra shop in the UK and was fitted for 30F. My BCD is 4.25. My above bust is very broad, narrowing rapidly to my full bust (39″) and even more to my below bust. As a result my above bust (33″-35″) underestimates my cup size while my below bust (28″-29″) overestimates my cup size. I wore AU36D for years because it was the smallest band in my cup size, but the bands were loose even new.
    When I looked up converters I couldn’t find US size equivalent to UK30F, and am not sure how that relates to your sizing anyway. I’ve finally got RTW that fit but want to make my own as they are expensive imports.
    The advice about sizing here just leaves me confused.

    Reply
    • Beverly Johnson
      Beverly Johnson says:

      You sound like you are an Omega. That means the root of the breast is smaller than the width of the breast at the fullest part. You will need to make a bra to test the fit, then make the adjustments to turn it into an Omega shape just for you. A 4.25 BCD would put you into a 30F in our sizing too but then you would further customize it by doing an Omega alteration. I have a blog post on that here called Alpha to Omega.

      Reply
  2. Sid
    Sid says:

    I am not sure why you recommend women use their high bust measurement to figure out their band size…. 80% of women have breast tissue up their and your bands measurement should not contain any breast tissue….I think according to this I would be a 32A/AA or something like that….but my ribbcage measures 25″ very tight, 27″ firm and 28″ loosely measured while my high bust measures about 31″ and my Full Bust measures about 32″. So in reality I wear about a 28DD, sometimes a 30D with a reduced band or very firm band.
    Why not just have your customers measure their actual rib cage/under bust directly under the breasts? This number is equivalent to the band size they need. In my experience the under bust measurement is the same as the band size about 90% of the time. Women with less breast tissue, more muscular torsos, or very sensitive torsos sometimes go up 1 band size when using this method. A women with a snug rib measurements of 24″ inches WILL be most comfortable in a 24 or 26 band with a 28 band riding up their back.
    I wish you would offer this method of measuring for your customers. While I do like the idea of BCD measuring, I think that band is highly inaccurate and results in a too loose band 85% of the time. Unless ofcourse your bands measure about a size smaller than most OTR bras do. Generally speaking a 30 band measures about 26″ flat and stretches to the appropriate 30″. Which is where I think they get the “add 4 inches” method for band sizing. Ofcourse it’s ridiculous now because our bra materials are ridiculously stretchy, so adding the 4″ to a 28″ rib measurement results in a 32 band which ofcourse would result in being far too loose and offering no support. A band MUST stretch around the torso in order to support it, it can’t just wrap around like a t-shirt.
    I am really curious to see what the flat and stretched measurements are of your bands in order to some how support the under bust by using the high bust method to figure out the band size.

    Reply
    • Beverly Johnson
      Beverly Johnson says:

      You must be buying European bra brands, where the rib cage size IS the band size. That’s not the case in North America, where the rib cage measurement PLUS 4″ equals the band size. Therefore a 28 band in European sizes is really a 32 in NA sizing. It is FAR more accurate to take the high bust measurement and not involve the rib cage at all, when making that first bra.

      Reply
      • Sid
        Sid says:

        No I live in the United States. North American and the United States are the most prone for bra fitters and women to be wearing an ill fitting bra. According to that I should be wearing a 32 band but your 32 band is big enough to wrap around my full bust… so no. Bras are made of 90% elastics. They stretch incredibly. In Europe, their system is built with the Plus 4 method built in to it. It makes no sense to take the highbust measurement for band…..your band does not sit there, it includes breast tissue. How can you can a snug firm fit from something that wraps loosely around your body? I really like you BCD measurement, but the fact of the matter is is that you are selling women bands that are not going to support their breasts. A size 32 band averages about 26-28 inches laying flat unstretched. But when you stretch that band is stretches to 31″-33″. This stretched band is what is going to support you, if you just wrapped a band around your body without stretching it, it will support nothing. Unless ofcourse you decide to make bras out of a material that will not stretch at all. Then yes, the plus 4 method is the one to follow.

        Reply
        • Beverly Johnson
          Beverly Johnson says:

          Actually, my bands are NOT 90% elastic. half of my bands are non-stretch (the front half). The back half is made of power net which has 40% stretch at most. My 32″ band stretches to 31-133″ when stretched and measures as you say 26-28″ laid flat. The BCD system uses the BCD measurement to determine the CUP that fits them (so the cup is independent of the band) then they use whichever band measurement fits them to their level of tightness. The band in any case is the easiest part of the bra to alter. Getting the cup to fit is much more important.

          Reply
  3. R
    R says:

    This may be an obvious question, but do I wear one of my existing bra’s when I measure? And if so, does the fit of that bra affect the accuracy of my measuring?

    Reply
    • Beverly Johnson
      Beverly Johnson says:

      Yes, wear a bra hopefully one without padding and not a sports bra as those will definityely affect the measuring. Just so you know I just released the Ruby bra, which is based on measuring the BCD way, rather than cup sizes.

      Reply
  4. Andrea
    Andrea says:

    Thank you, Beverly, for such a clearly written article on measuring for bra size. You are a gifted teacher!

    Reply
  5. Elena
    Elena says:

    I have read all the posts above but still have some uncertainty. My measurements: HB 36, FB 42-44 (every time it is different but always within these figures), rib case 35, BCD 4.
    HB/FB method gives me the 30-38 E-H pattern
    BCD method yields in the 36 AAA-D
    As far as I understand my measurements fall somewhere between two patterns.
    Which do I prefer?

    Reply
    • Beverly Johnson
      Beverly Johnson says:

      I almost always go with the BCD but I find it hard to believe you are only a 4.0 BCD. Did you measure with a seamed bra on…one that fits?

      Reply
      • Elena
        Elena says:

        I made measurements several times – with a seamed bra that fits and without any, that is to say, “live”. 4.0 BCD is ok. At first, I didn’t understand why my FB figures are so different. If I measure on the band I get 42. If I measure a little bit above the band but on the “fatty underarm cushions” I see 44. I suppose 42 is better. Am I right?

        Reply
          • Elena
            Elena says:

            As soon as I choose and buy a pattern I will definitely try sewing the bra.

            So, having HB 36 and BCD 4 I should buy 30-38 AAA-D (pink) Shelley Full Band Bra Pattern.
            Am I right? I live far-far away abroad. Delivery of the pattern is time and money consuming. I wouldn’t like to end up making a mistake.

  6. Judith
    Judith says:

    Hi Beverly,
    So far I have made 9 of your bras for my daughters and myself. We love them. I made a 42C for daughter A. Daughter B tried it on; the cups were fine but the band was 2 1/4″ too long. I adjusted the original pattern and the new bra fit perfectly. So well in fact that daughter B wants more. Is there a way to calculate what size bra I actually made for daughter B?

    Reply
    • Beverly V. Johnson
      Beverly V. Johnson says:

      I would measure the band size you made against the patterns in the envelope. I think it would be close to the 40 band size.
      However if you are looking to make the “whole pattern”, there is no pattern in her size in that pattern range BLUE.
      You made a cup with a 4.25 BCD and a 42-2 = 40 band size. There is no pattern for that combination in the BLUE range.
      You should just shorten the band for daughter B and use the same cups as A. Then you won’t have to buy another pattern!

      Reply
  7. genise
    genise says:

    I am having a difficulty with the BCD method. I put on my Elomi el4010/cah (38H) bra and took the measurements. From my nipple to the underwire of the bra it is 4.5 inches and my over bust is 41 and my under bust (rib cage) is 38 so I am not sure which way to go since my size is not in your chart above. Your assistance is greatly needed. This will be my first bra.

    Reply
    • Beverly Johnson
      Beverly Johnson says:

      This bra has a raised cross cup seamline so taking the BCD will not be accurate. The brand also uses a different method of measuring the size for the band. If your rib cage is 38, you will need a 42 band size in my patterns. When you say “over bust of 41, do you mean the high bust or the full bust is 41”? If you buy the 38H in my patterns, the band will be too short.

      Reply
      • Genise
        Genise says:

        I meant the high bust. Would the cup size be the same as yours and how does that translate to the underwire? Thanks again for your assistance.

        Reply
      • GENISE HEARD
        GENISE HEARD says:

        I am revisiting this, sadly a year later, but better late then never. Since this is the best fitting bra that I have what do you suggest that I do to determine the right pattern to purchase. As mentioned in my previous post the 41 is the high bust.

        Reply
        • Beverly Johnson
          Beverly Johnson says:

          Actually you can measure your current bra from the apex (nipple area) straight down to the wire line. That is the Bottom Cup Depth and the size I would try first.

          Reply
  8. Lori
    Lori says:

    Hi Beverly, I’m still having trouble determining the best bra size. My measurements are: HB 32″ FB 37.5″ Underbust 30″, BCD 5.25″. I have a small ribcage and the breast tissue comes up fairly high on my chest. The HB/FB method gives me a 32E. The BCD method gives me the option of a 30H or a 34G. I currently have RTW bras by Fantasie and Panache which are 30G but the center doesn’t sit flat against my breastbone and the straps dig into my shoulders (I have those deep grooves you’ve referred to). I wear the band on the tightest hook, but feel like it should be tighter to be supportive enough to take the weight off the straps. Also the wires reach almost to my back! I was hoping to make a bra that actually fits. Am I a hopeless case?

    Reply
    • Beverly Johnson
      Beverly Johnson says:

      It is possible that your RTW bras do not fit if they still do not reach back to the wall. But I use the BCD to gauge the size as I find it most accurate. So a 30H or 34G (even though in RTW it doesn’t fit well) is a place to start. You also sound like you might be an Omega shape breast. That’s one where the wire is a small size but the breast is larger. You have to shrink the cup at the wire line only to fit into the appropriate frame size. I wrote a blog post on it called Alpha to Omega. Just click the link to read it. Good luck!

      Reply
      • Lori
        Lori says:

        Revelation! Your Omega blog was exactly me. Now I understand why I can’t find RTW bras that fit! I guess I’ll just have to dive into making my own. A comfortable, supportive bra may not be just a dream after all. Thank you so much!

        Reply
  9. Michele
    Michele says:

    I’m taking your Craftsy class and I’m just curious if you have any guidelines or tips on body shape that may make a woman fall into that category of women that the high bust-full bust measurement technique doesn’t work for?

    I wouldn’t consider myself as having a small rib cage per se or athletic build, but my RTW size and the pattern size I’m measuring based on high bust-full bust measurements are widely different. My RTW size is 34G but I measure 38B using high bust-full bust. Thoughts?

    Reply
  10. Claire
    Claire says:

    Having broad shoulders and less than full breasts (thanks to the babies!) methods 1 and 2 have just not worked for me at all! I know we disregard our ready to wear sizes, but I only have to glance at the pieces of the bra patterns I have to know that I am NOT an A cup. Having measured using method 3, I’ve come out at 38E and have more confidence that this is a good starting place. I’m now going to continue watching your Craftsy course and hopefully come out the other end with a beautifully fitting bra! So excited!

    Reply
  11. Beverly Johnson
    Beverly Johnson says:

    The duoplex in the kit is not very stretchy, not nearly stretchy enough for panties. You could, however use a bit of it as a front panel, just to get the colour and fabric into the panties as trim.

    Reply
  12. Corina Kostreba
    Corina Kostreba says:

    Hi Beverly; I have your Craftsy pinup pattern. This posting was very informative as I too have side tissue that refused to get with the program and spills out over the sides. You mentioned that with the proper bra it could be trained back into place, so this gives me hope. Also wondering if there is enough fabric in the kit for me to make a panty or should just order more of your fabric??

    Reply
  13. Beverly Johnson
    Beverly Johnson says:

    No it is not hopeless but your best bet would be the use the Bottom Cup Depth method of measuring. That will allow you to see how large the actual breast is (in volume, so to speak) apart from the band size. Once you find the equivalent cup that fits, we can easily make the band larger as needed. Don't give up on this – I am certain we can get you into the right pattern!
    It may take a bit of customizing but the results will be well worth the effort!

    Reply
  14. Beverly Johnson
    Beverly Johnson says:

    I have found that European bra manufacturers differ greatly from their American counterparts, so that's why you can subtract and we have to add. That's why it is frustrating to buy bras, as a customer is almost always on their own, unless they have a good bra shop nearby that has trained fitters.That's why we sew our own – to customize the fit!

    Reply
  15. LissaB
    LissaB says:

    I've wanted to take your first Craftsy class for a long time, but none of the pattern sizes sold on your site will fit. I'm a very large woman and always have a hard time finding bras to fit me. My underbust is about 55-56", so if I add 4-6" to that, I don't even think they make bras that big. Another issue is measuring the full bust. Since there is a lot of "side fluff", that measurement is hard to get and isn't really a good indicator of how big my breasts are. The "fluff" goes all the way around the side into the back, so the measurement ends being around 65". Some of that can be scooped into a cup, but not all of it, so I'm not sure how to find out my proper size. I currently buy 54C or 54D, which has pretty limited options and none have underwires. I buy front-close bras because it's impossible to reach around back to close a bra. Is it hopeless? Do I just stick with ready made bras?

    Reply
  16. Beverly Johnson
    Beverly Johnson says:

    The breast tissue should ideally be inside the bra cup, and sometimes it takes a few months to re-direct it in there even with a correctly fitting bra. What did you measure using the BCD method. I suspect you will be the 30E and perhaps without any more info on my part, that would be the place to start. I don't use DD (that is E in my patterns)

    Reply
  17. Anonymous
    Anonymous says:

    Hi fairy bra mother,
    I have your pattern, and I have ordered a kit I love the colour Fuchsia pink . and would love to have a go. I am not what you call competent at sewing person .
    I have searched for a bra to fit for years.
    I have breast feeding tissue under each arm which in it's day gave milk.I am now 62 years so my breast tissue is limp almost fluid.
    When you talk about getting all the tissue into the bra where does this put me. I am a small framed person and I seem to be around a 30 E or DD ,when I mesured your way I came out at a 32 C, but it is not a fit I have to much tissue.
    Is it better to have the extra breast feeding tissue outside the bra or in. the 30 E seems to fit better( Freya ) but the top cups are loose, whilst standing but if I bend over the breast tissue fits into the bra cup. Hence what I said about fluid tissue.I am sure you have come across women like me but I am not sure what to do. the kit I ordered was for 30 E. Help please

    Reply
  18. Gavanna patterns/ Tina olsson
    Gavanna patterns/ Tina olsson says:

    Hello Beverly! I found this very interesting! I have been a bra seller for 4 years in total, in a big department store and a smaller chain, and as you point out we use method number 1. But I have never come across the advice to ADD width from your ribcage or under-bust measure. this is unheard of in my business, we REDUCE it! I find that a bra usually fits excellent if between 10 and 15 cm is taken off. That is 4-6 inches. (And we follow every single customer into the fitting room and look at them wearing the bra, and a customer usually tries on 4-10 bras to get a good fit, so I have seen a lot of bras! )
    Now, this measuring method do have some negative effects too. The bra band will fit very tight around the body, often causing quite bit of flesh sort of "oozing out," mostly in the back. The customer has to be convinced that this is not a problem with the bra size, but her amount of time spent in the gym 🙂
    There is also a limited number of producers that make a sufficient number of sizes, especially the ones most needed, with a small band ( sizes 30 and 32) with large enough cups ( let's say DD-G) so I sometimes ended up not having the size the customer actually needed.
    So all in all, a less serious seller, with a limited number of models, types and shapes, (as in a small chain selling only their own brand ) may end up not being totally honest with the customer.

    But I live in Sweden, and my bra selling all took place in Stockholm, and habits can be different in other countries? I have actually never asked for bra- advice anywhere else so this is just from my limited horizon.

    But apart from that little surprise I find your instructions absolutely clear and correct, so keep on the good work!
    I have myself only just started to try to make bras, and it's an exciting new area to say the least!
    Best regards, Tina

    Reply
  19. Beverly Johnson
    Beverly Johnson says:

    Great question! Measure from the seamline between thee cup and the wire. If there is no seamline there (as in a partial band bra) then measure from the topstitching along the inside edge of the wire to determine the BCD

    Reply
  20. scooter
    scooter says:

    Ha! Ditto here, and I suspect similar stories for a lot of women in our size range. Though my sizes by the first two methods are 32AA and 30A, there's no way I could wear them–I quad-boob out of a 30B, and a 32 band rides up my (28") back, but my breast tissue's spread all over my torso, with wide and tall roots. I make a 30C and reduce bottom cup depth…and now I'm going to need to look up how much I reduced it, because I'm curious if it aligns with Beverly's table. 🙂

    Reply
  21. Jeannie H
    Jeannie H says:

    This is very helpful information. The BCD may be the thing that helps me zero in on my correct size. Method #1 is a total disaster for me. It isn't even in the ballpark. Method #2 gets me in the ballpark, but it isn't exact.

    You mention using sample bras to access starting size in your classes. Do you ever rent these sample bras out? This would be very helpful for those of us who cannot attend a class.

    I made a couple of tester cups for the PU Girls Classic bra, and from a bra kit I cut the one that seemed right. Before I could sew it up I lost a large amount of weight. I am going to have to start over with sizing. I sure hope that I am still in the size range of patterns I purchased. If not I guess I buy new patterns for the Classic and the Shelley (which is the actual style I intend to use once I have a well fitting pattern).

    Reply
  22. Anonymous
    Anonymous says:

    Thanks for this post Beverly! Method 1 is a disaster for me – yields a 38F. Method 2 HB and FB yields a 34J, which is too big.
    Method 3 BCD is closest, yielding a 34G (which is too small cup, too big band for me). In the Shelley pattern I adapted the 32H to fit by widening the bottom of the band about 1" total, and moving strap attachment downward, which effectively decreased upper cup volume a bit… yielding a pretty decent fit. Omega shape issues 🙂 The Shelley bra is a truly great one! I wish you offered them in PDF format to save us on shipping costs!
    LP

    Reply
  23. Anonymous
    Anonymous says:

    Terrific addition to bra fitting. I always found it suspicious that a 3 dimensional object was determined with 2 measurements. Seems impossible. I also think that measurements should include a consideration for breast width. I suppose that is covered with wire widths. Thanks so much for article. Look forward to the Craftsy class!
    Anne

    Reply
  24. Lyndle
    Lyndle says:

    Great article! Tomorrow night I'll have to try them all. Unfortunately at the moment the best fitting bra i have is a (thin) foam one with no seams, but I'd really like to be able to sew one and get it to fit. I must do it! I have both your craftsy class and a pattern of yours I win last year on Erin's giveaway, so no excuses!

    Reply
  25. SewingZoe
    SewingZoe says:

    Beverly, this is a brilliant post, very helpful to all of us. Thank you. I can't wait to see your next class on Craftsy and after that the next one and the next one… ect.

    Reply
  26. katherine h
    katherine h says:

    This is the first time I have seen the bottom cup depth method. It puts me at 34AAA. Method 1 & 2 put me at 34B. I find 34B wires to be the best fit but there will always be too much volume in the cup for me….guess that is why I sew my own!

    Reply

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