Home Finding your bra size

Finding your bra size

So, you’ve stumbled upon my blog and learned that there’s a world of sizes out there beyond 32-38 A-DD. According to studies, somewhere between 65%-85% of women are wearing the wrong bra size. Are you guilty?Never fear young grasshopper, I (with the help of many lovely resources) am here to help. We need to free those boobs from titty jail!

So, without further adieu here is how to measure your UK bra size. You will need a soft tape measure and a mirror (or a friend). You’ll need to do this with bare breasts and you’ll be using inches.

Step 1: Measure under your bust keeping the tape measure parallel to the ground. Keep the tape measure as snug as you’d like a bra to fit.

Step 2: Write the number you get down. Round it up to the nearest even number. This is your band measurement.

Step 3: Measure around the fullest point of your bust while leaning (again with the tape measure parallel to the ground). Do not pull tight or distort your breast tissue.

Step 4: Subtract the number you got in step 1 (pre-rounding) from the number you got in step 3. This will give you your cup size with 1=A, 2=B, 3=C, 4=D, 5=DD, 6=E, 7=F, 8=FF, 9=G, 10=GG (etc). If you are between two numbers, try both sizes!

I know, I know, this sounds like a lot of work. So, for motivation here is a bra-fit before and after of me:

These photos were taken on the same day. Left: VS 32D Right: 26FF Comexim

These photos were taken on the same day. Left: VS 32D Right: 26FF Comexim.

If all of the math still seems like too much effort (I feel you there) you can use this bra size calculator.

So now, armed with your new size, you may feel a little bit of panic. How could I possibly be an F cup? Well, cup size is NOT static. Contrary to what the media portrays, there is no such thing as a “D cup”. A 26D is half the size of a 32D. A 34D is much smaller than a 38D. If you still have sticker shock about your size, take a look at it on the bra band project. Hopefully you’ll find a titty-twin 🙂

Questions? Feel free to email me at thepetitecollegiate@gmail.com

Other Informational Resources:

A Bra that Fits: Beginner’s Guide


The Kewl Blog: How to Choose the Right Bra Size and Style (I’m quoted in this!)

Busty Resources Wikia: Scoop and Swoop

Bras and Body Image: Putting on your Bra

An Enhanced Experience: Fitting with Implants


Daisy white August 27, 2016 at 1:13 pm

this article is so amazing thanks for publishing this type of stuff

Krisztina August 10, 2016 at 2:11 am

Hi! I have gone through this page, and I have a question. What kind of sizing do you follow? Can you send the source? Because in this case I am supposed to wear a 32F bra (underbust 31.8, and overbust 38.6), but I am a very comfortable 32D, and also as per the pattern grading the difference structure is like this: A=5 inches, B=6inches, C=7inches, D=8 inches, etc…
Please send me your reference, because I find it very interesting, how can be such difference in two systems?

The Petite Collegiate August 11, 2016 at 11:43 am

Hi! Most of the brands I wear use UK sizing, and that’s what’s detailed here, but it’s fairly easy to covert to any other sizes. Almost all brands use the 1 inch per cup grading scale (so with an A being 1 inch different etc.) with the exception of some European brands who go by 2cm grading increments instead. Here’s a nice article about sizing: http://www.barenecessities.com/feature.aspx?pagename=fit_sizing&amsk=riejwn8874
My guess is that you’ve got a bit of a snugger cup than textbook fitting would prefer. Everyone has their own preferences, and it’s totally valid to wear any size you want to. What brand are you wearing? I’ve honestly never heard of a system in which an A cup would be 5 inches different than the under bust. A long time ago, there used to be a system where bra companies advised women to add 4 inches to their underbust and then calculate the difference (So by that system you would wear a 36B/C). I’m interested to hear about what sizing system you’ve been following, because it’s definitely unique!

Krisztina August 18, 2016 at 3:54 am

Hi! It’s an indeed interesting discussion. I agree that different brands may follow different sizing pattern. First let me list the bras that I have in my wardrobe and I use nowadays: Victoria’s Secret (2 pcs), Intimissimi (3pcs), Wacoal (1pc), Bordelle (1pc), Agent Provocateur (2pcs), Passionata (1pc). Right now I don’t have, but I also purchase and use Palmers, Etam, Chantelle, La Senza, CK, RougeGorge, Aubade and Eres (I love the brand, but very less availability in 32D size, so I don’t purchase very often). All my bras in my wardrobe are 32D, except one of the Agent Provocateur, which is made of woven satin, with less elasticity, so that is a 34C size, and the Bordelle one which is Bordelle size “M”, that is equal to 32D. And I wear the same 32D in all other listed brands. I go to fitting sessions very frequently (once in 6 months) and since my weight is constant my size of 32D has been again and again reconfirmed. But you might be right that I may not wear the proper textbook fitting bra, as I am not sure what we mean under textbook fitting bra. 🙂
You are right, the most important is to have a clue how to convert our measurement into the proper size of the given brand. In order to get the info, as you rightly wrote the first and most important is the rib cage (underbust) measurement. Nowadays all brands agree on what is measured is gonna be the size, as you also wrote. Earlier mostly at the time of woven cut and sew bras it was suggested to add a couple of inches to the measured underbust, for a simple reason, because a woman’s body is changing during her menstruation cycle, and woven fabrics didn’t have the elasticity to follow the changes. The more elastic the fabrics became, the less additional inches were used. You have mentioned 5″, but for example 20 years ago it was only 2″, and slowly slowly we reached to the nowadays level, when we take whatever is measured.
The second part is the cup, and I think this is where the story becomes interesting. The cup size is always calculated by taking the difference of the underbust and the overbust. This is why I asked which sizing do you follow? I am pretty surprised on Bare Necessity’s link, what you have sent, and I cannot say that it’s wrong as you are following it, and you say it’s working completely for you, but I am surprised as they also sell Wacoal, that I do wear, and at least in those stores from where I bought my Wacoal bras, I was always guided by the system that I explained above. As you mentioned European brands go by 2 cm grading (that is the EURO sizing), which is true. The grading system is 2cm-2cm, but it doesn’t start with 2 cm difference (between under and overbust). “A cup” is taken when the difference is 12-14 cm, “B cup” is taken when the difference is 14-16cm, the difference in case of “C cup” is 16-18 cm, etc… If you calculate these numbers in inches you will get the following: A cup=4.7-5.5inches, B cup=5.5-6.3 inches, C cup=6.3-7 inches, etc. As you see, what I told you 5,6,7 etc inches are basically somewhat similar to this sizing, we can say that the EURO sizing is more precise that the one inches, as the grading is 2 cms, instead of the 2.54 cms. You can check out the actual pattern making guidelines in Ann Haggar’s Pattern Cutting for Lingerie, Beachwear and Leisurewear. You can find this above-mentioned cup sizing on page 64 (second edition), you will find the same structure.
As per Bare Necessity’s opinion the A cup is when the difference of the underbust and overbust is 1 inch, which means only 2.54 cms. For me this system is unique, as on an average basis only young teenager girls have such difference (I know that there are few adults with very small breasts, but we cannot consider those females as the main average, and all my respect to those ladies, one of my best friend is also facing issues, as she has only 2 inches difference, and she cannot wear anything else just bralettes.). I would also love to know your actual measurements, as I might missed it out when I was reading the article, and also which brands you wear on regular basis.

Krisztina August 18, 2016 at 8:50 am

Hi again! I couldn’t stand thinking how can our ways be so different, and I am happy to say I got the answer, I guess you follow the US way of measuring yourself! The first step what you write is not actual underbust measurement: you actually keep the measuring tape at the band level in the back, and then get it to the front under your each arms, and around the front. The measurement tape is running just above your bust, where your strap meets the cup. You take it as the underbust measurement. After this you measure at the nipple level, and then subtract Number A from Number B. If you do this, then actually 1 inch means A cup, 2 inches mean B cup, etc. With this technique my 32D is coming properly 🙂 Just check the “Step 1” coz it’s a bit misguiding, if you check the site, Bare Necessity (what you have sent me), there it’s also mentioned that there are two ways of measuring, but after that they don’t specify how to calculate the cup size. 🙂

a. April 29, 2016 at 12:34 pm

Wow, this site is the coolest thing ever.
I have finally gotten my act together in regards to lingerie, and after not being fitted for literally years, I did a self-measure last fall. To my utter amazement I measured 28D – I didn’t know there was such a thing, and how could I be a D when I’m kinda teeny?! But there it was, in black and white (and I used several online calculators to recheck). Sure enough… the bras fit, I don’t have empty space in the cup, and I look amazing in a properly fitted bra!
Thanks for being a part of my continuing education!

thepetitecollegiate April 29, 2016 at 6:18 pm

I’m so glad its been helpful! And congratulations on finding your size! Self-measuring is awesome 🙂 It lets you take your comfort into your own hands.

Helen April 15, 2016 at 5:27 am

Pleased to see this! Going to drop you a line when I have some time as I wouldn’t mind talking to you about a sports bra campaign I want to unleash…

thepetitecollegiate April 15, 2016 at 10:36 pm

Absolutely! I’m always happy to collaborate or just chat 🙂


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