This is the task that every women should do before starting the sometimes grueling adventure to buy a bra. Whether or not you are going to be fitted when at the store, it should still be knowledge to you of the rough estimate. It will also help in those cases when you think that they measured you wrong. It can save time and money.
Also, don’t be scared if you happen to find out you are a 32E instead of a 38B. it doesn’t mean you are large, it just means you were measured wrong and you will probably find that 32E to be more comfortable and fitting. Remember, there are the vast majority of women who are in the wrong sizes.
First!
You gotta have a measuring tape, or some other sure way of getting a rough estimation of your bust. No bra or shirt can be on for this, as it can mess up the numbers.
Second!
Tightly run the measuring tape below your breasts, keeping it even across. If you are comfortable, it’s better having someone else do this part for you, or even a mirror would do. This number here is your Band Size.
Third!
This is why not having a bra on comes in handy. If you were to have a bra on, the measurement you would most likely get would be for that cup size. And what would be the point in measuring for your cup size, then? None! So you must not have one on. You most likely will have to bend over at about a 90 degree angle to get it accurate, but that’s only the case if, like me, you are slightly droopy. This number you get while bending over is your Cup Size.
Fourth!
Do some simply math! Subtract the Band from the Cup (Cup Size – Band Size) and that is the number that will help you figure out of your cup size. Each inch, equals one.
(note: 2.5cm=1inch)
Cup Sizes!
1 inch = A(US)/A(UK)
2 inch = B(US/B(UK)
3 inch = C(US)/C(UK)
4 inch = D(US)/D(UK)
This is where they start to differ a bit!
5 inch = DD/E(US)/DD(UK)
6 inch = DDD/F(US)/E(UK)
7 inch = G(US)/F(UK)
8 inch = H(US)/FF(UK)
9 inch = I(US)/G(UK)
10 inch = J(US)/GG(UK)
11 inch = K(US)/H(UK)
12 inch = L(US)/HH(UK)
13 inch = M(US)/J(UK)
14 inch = N(US)/JJ(UK)
15 inch = O(US)/K(UK)
16 inch = P/KK(UK)
17 inch = –/L(UK)
18 inch = –/LL(UK)
Now, you’ll probably notice that the Cup Sizes stop on the US side at O, and I’m even pushing it. You’d be hard pressed to find any of those cup sizes, let alone anything larger. Which is why I added the UK sizing as well. They go up larger, and have a wider variety of Band and Cup Sizes.
I’ll give you my measurements as an example. I am 29.5 inches for my Band Size and 43 inches for my Cup Size. This would put me at, roughly 30M/28N(US)/30J/28JJ(UK)
Note!
The band size is usually close to your waist measurement, most likely between two or three inches. But, of course, not everyone is the same.
Comment with any questions or your measurements, and I’ll be glad to help out!
Voluptuous and Beautiful 
I found your site while browsing the web in desperation trying to find bras that will fit. I have an abnormal figure and have a difficult time finding anything that will work. Usually I buy the largest size in both back and cup in the store and have my mom alter the back to fit my measurement of 29 inches. Even with alterations they never fit right. The bigger problem is that my bust is 50+ inches. I say plus because I have not measured in a while out of fear. I would love to find a bra that is my “real” size and not have shoulder grooves or pain anymore. Also colors other than white or tan would be great as well! Do you know of any bras that will minimize my chest? I am about a size 4 everywhere else so I would like to look a little less freakish. I am in my first year of college and would love to find something with a better fit for upcoming formals. How about strapless? Thank you for your help.
I can sympathize with how difficult this can be, even if I haven’t experienced this to such an extent as you have. I know of no minimizers as I see no use of them personally, but I am now thinking of creating a post for such things.
Have you tried Ewa Michalak? Her bras can be custom made and it is possible that she could create a bra for you and she has wonderful selections beside tan or white, yet even the tan and whites are quite gorgeous!
I’m sorry I’m unable to help more. I’ll begin my search today in hopes of helping you. I wish you the best and hope to hear back from you.
I’ve found that when you don’t measure, it’s like moving your pawn on a bra size board game–move forward one cup, move backward one band–based on comfort and change over time. But when you measure, it’s like having a GPS to know where you are at all times.
I first discovered this site and various similar ones in early 2013 as a 12-year-old 7th grader. I noticed that my 34C didn’t fit, but I wasn’t sure what the problem was–the straps? The cups? The band? I got frustrated because American Girl kept telling me to add inches, even though it kept giving me a size that didn’t fit. Then, when I discovered this method, I was like, “whoa!” I looked like a (supposed) C/D cup, and I wasn’t super skinny, so how could I have been a 28F? Turns out, it actually fit me like nothing else. Now I’m a 28G approaching an H.
Thanks for this blog, giving girls the CORRECT measurements!