How To Find Your Bra Size: Video Guide

Nov 27, 2023 | Hurray for Lingerie, Q&A, Style Solutions, Underneath | 0 comments

Hurray! It’s time to answer the number one asked question in my TikTok comment: how do you measure for your bra size? I’m finally going to walk you through the process step by step below. FYi, my name is Kimmay and I’m an undergarment educator who has been fitting folks from AA-N cup since 2005. If you, too, have been wondering, “how do you find my bra size?” I’m going to walk you through finding your bra size starting points. Let’s do this!

Before we measure anything, I want to make it super clear that whatever number you get here is not who you are. What I mean is that not only is this measurement going to give us just a place to start, so it’s not really a definitive answer on your size, you are also not a size. You are a divinely created, generous, beautiful human being that happens to wear a certain size in something, or a certain size happens to fit well. That’s it. 

As I mention in my #MoreThanMyNumbers posts, numbers, like bra size measurements and starting points, are information, not a definition of who you are. In other words, a size is what you wear, not who you are. 

Oh, and if this feels overwhelming for you, remember you can always go in to work with a fitter or I have a course called Bra Confidence and Comfort that walks you through all of this, plus has great shopping guides and tons of emotional support.

Part 1 – Finding Your Bra Size: Underbust


How to measure your bra size starting point part 1 - your underbust! This is my most asked question as a professional bra fitter and I’m finally answering it!🎉👙 Stay tuned for part 2 coming soon! #brasize #brasizeguide #brasizemeasuring #measuringbrasize #howtofindyourbrasize #cupsize #bandsize #professionalbrafitter #brafittingspecialist #brafitting #undergarmenteducator #brafitterlife #brasizingbasics #brafittinghelp #brasizingtips

♬ Calm - Faneo sound

What you’ll need:

  • A soft measuring tape in inches. (For my folks who are in the EU, we are going to use inches because it is easier.) You can find these at a drugstore or even the dollar store.
  • A bra. Everybody asks me if they should measure with their bra on or off. I suggest on. If you are wearing a bra that does not fit well, then the measurement that you’re going to get probably isn’t going to be perfectly accurate, but we’re not going for perfection. We’re going for a place to start. The key thing, though, is that you want to make sure that bra does not have any pushup padding or is not a minimizer. Next, put your bra on. 

Step 1: measure the underbust and calculate the first band size

  • With your bra on, get as close to the bust root (where your bust actually attaches to your body) as you possibly can.
  • Take the measuring tape, and wrap it around you. What is really key here is that you want to stay parallel to the floor with this measuring tape from directly underneath the bust straight back. As you can see in the video, directly underneath the bust, straight back. 
  • Take a deep breath in. And out. Just breathe like a human when you take this measurement. You want the tape to be nice and snug, like a little hug on your body.
  • Record your measurement in inches. I got 33.5″.
  • Take that number and round it up to the nearest even number. If you got exactly on an even number, like 36, you’ll just stick with 36. I got 33.5″, which means I’m going to start with 34. 
  • Move on to the next step!

Part 2 – Finding Your Bra Size: Bust


How to find your bra size part 2 - Measuring the fullest part of your bust!👙 Make sure to watch part 1 to learn how to measure your underbust, and stay tuned for part 3 where we’ll be putting everything together to calculate your size! #brasize #brasizeguide #brasizemeasuring #measuringbrasize #brasizingtips #brasizinghelp #brasizingbasics #brasizecalculator #howtofindyourbrasize #bandsize #cupsize #undergarmenteducator #professionalbrafitter #brafittingspecialist

♬ Lo-fi hip hop - NAO-K

Step 2: Measure your bust 

  • With that same measuring tape that we used before, go around your body once again. This time you’re going to go across the fullest part of your bust. This is usually right across where the nips are.

TIP: By the way, if you need some support doing this, you can always use the buddy system. If you’re DIYing it, I highly suggest using a mirror, so that when you are going right around, you can also then look either in the phone or the mirror, and make sure that it is then parallel to the floor, straight back from the fullest part of your body.

  • This time, do NOT squeeze in like a hug. We’re just going to let it gently kiss your body all the way around and stay nice and flush. Remember: snug like a hug for the band, and like a little kiss across the bust.
  • Once again, take a deep breath in. And out.  Relax and breathe like a human, knowing that this number is just information and not a definition of who you are.
  • Once you’ve done that, you can take a look down and make that measurement. I’m getting just about 40″. How about you? Write yours down. Now you have recorded your bust measurement.

A note: If this number changed or changes on you, guess what? You are still as beautiful today as you were yesterday and will be tomorrow.

Part 3 – Finding Your Bra Size: Calculate

Step 3: Calculate your first starting size 

  • Let’s calculate your first “bra size starting point” using the measurements that we found in parts one and two.

Remember: your confidence and comfort in a bra all comes down to how something fits. Bras are a lot like jeans where you could wear one size in one brand or one size in one rise and a totally different one in another one. So this is just to give us a really great place to start.

  • Band size: My first measurement was 33.5″ and I rounded up to the nearest even number which was 34. So my first band size is 34. 
  • Bust measurement: Then across my bust, I got 40 inches, so I’m going to take my bust measurement and subtract my band size.

Note: Subtract the band size (not the band measurement) from the bust measurement. Use that even number that we calculated

  • Bust measurement – Band size = ? For me:  40 – 34  =  6 

Now what do we do with the 6? This is just the difference between your bust and band. We’ll use it to calculate a cup size, using one letter for every single inch difference. 

  • So here in the US that means that would be A, B, C, D, DD (E ), DDD (F). 
  • So my first bra size that I’m going to start with is a 34DDD, which happens to be the size that I wear most often.

Note: That was pretty accurate for me. Keep in mind, sometimes these numbers are not exactly accurate, but hopefully it gives you a little bit more information of where to go on the bra size spectrum because y’all there are 275 different bra sizes out there.

Next you’ll find a size to compare the fit! Keep going. You are doing great!

Part 4 – Finding Your Bra Size: Sister Size

Step 4: Find Your Sister Size

  • Let’s find your second starting size or your “Sister Size“. 34DDD/F was my first starting size. Then, we want to find an alternative size that we can use to sort of compare and just see how things fit by going up one band, down one cup! 
  • To find that, go one band size up. So from 34, we go to 36, since band sizes in the US use even numbers. 
  • Then when we go up to that 36, just to remain in the same cup size volume as that 34DDD, we actually need to go down one cup size. That’s because cup size is relative to band size.
  • So from 34DDD, I’m going to go to a 36DD. And those are the two sizes that I am then going to compare whenever I try on bras. Record yours! What two sizes did you get?

BTW, then using these two size you’ll want to ask yourself: Which is fitting better? Which band size is really snug and working for me? Would any adjustments up or down in band or cup fit better? This is also helpful to determine if you want to change the style or cup coverage. But just for general purposes, those are the two sizes that I usually would start with. 

You did it! Up next, you can calculate your international bra sizes. 

Part 5 – Finding Your Bra Size: International Size

Step 5: Calculate your international size

We’ve already calculated your first two starting points and now I want to give you the information for finding your bra size in different countries. A lot of bras are either imported to the US and North America, or you might be shopping someplace else in the world. So let’s make sure that you are getting the sizes that you need no matter where you shop.

US Bra Cup Sizes

US sizes, go: A, B, C, D, DD, DDD, (Noting that DD and DDD just replace E and F) and then goes right back to G, H, I, J  and so forth and so on right up the alphabet. 

EU Bra Cup Sizes

In European sizes, they actually keep it super simple and they just go right up the alphabet. So A, B, C, D, E, F, G, H, I, J, K, so forth and so on. So you’ll count your cup size by using the alphabet as is.

UK Bra Cup Sizes

However, in the UK, things get a little bit different. UK bra cup sizing is A, B, C, D, DD, E, F, FF, G, GG, H, HH, J, JJ, K, KK…

  • Note that DD and E are a cup size different.
  • Then it picks up with F, FF, G, GG, H, HH
  • They skip I completely. 
  • Then it goes right back to J, JJ, K, KK, and so forth and so on.

So my bust and band circumference difference was 6 inches, which means in UK sizing, I would go A, B, C, D, DD, E,  which is different than what I was wearing in US sizes. This is such great information to know, as so many bra brands from the UK are amazing, especially for small band, full cup bras. 


Hurray! You’ve done it! I know this can sound confusing, and these sizes may be so different from what you usually wear. Don’t worry, you’re learning! It gets easier and I’m here to help.

I have a really great course called Bra Confidence and Comfort that can actually walk you through this. I’ve got charts that go with this to make it easy so you don’t have to do this bra math. And you can always work with your local fitter who can just help you find these sizes.

In the end, the size is really just the starting point. Then, you need to get what fits. Because after all, you are not your numbers. Numbers are just information, not a definition. A size is what you wear, not who you are. Below you can grab my free Fit Guide to check in on your current fit, compare the fit of your two starting sizes, and find more comfort. Whether you DIY it or work with a fitter, this information can empower you to make a loving and informed decision about what you wear right over your heart. Hurray! 

Free Bra Class

Want to wear a bra without ripping it off at the end of the day? Watch How to Find a Comfortable Bra Fit For Your Body WITHOUT Wasting Your Money on Bras You Dread Wearing! Plus, you'll also get Kimmay's Bra Fit Guide, and a taste of Bra Confidence & Comfort™. Watch now and don't spend another minute feeling uncomfortable in your bra.

Your Turn: Do you feel you know more about how to find your bra size? Did you give my step-by-step instructions a try? Share with me over at @hurraykimmay on Instagram!