How Do You Measure Your Bra Size at Home? Let’s Learn Together.

I’m going to be 100% honest with you. I never wear regular bras with cups. I stick to sports bras. Why? You might ask. Simply put: they never fit my body correctly. Look, I can’t even blame a specific brand because the truth is… I have NO idea how to measure myself to even buy the correct size (gotta love “oh this looks big enough” shopping). 

As of Summer 2023, that stops. 

I had to call my best connect for all things fashion-fitting advice and for once, it’s not my mother. Friend, I got the tips and tricks to finding the perfect fit-like-a-glove bra from none other than Jennifer Johnson – Design Director at POPFLEX

Signs of a Poor Fitting Bra

I told you I’m going to be 100% honest with you… if you look like the image above when you slip into your bra… it’s not fitting you properly. 


I know I know. When Jennifer ever-so-politely dropped knowledge on signs of a poor fitting bra, I sat there jotting down notes but not for you… for ME. With my right boob popping out of the top of my bra and my bra band halfway up my back begging for me to take it off, I felt so… seen. BUT this is the beauty of fashion education. You (cry a little) live and learn. 

Here’s what to look out for:

  • Boob spillage 
  • Wrinkly cups
  • The bottom band should be leveled, which can be done by tightening or loosening the straps
  • The back band should not be super high and should rest comfortably on your mid-back 
  • You should not be able to stick more than 1 finger under the bottom band. If you can, this means it’s too loose
  • Bra straps sliding off (you want a secure fit) 


How to Measure Your Bra Size

We have to learn at some point. Let’s get into it. 

Step 1: Grab a soft measuring tape. 

And I know you better not go into your closet and get that super hard measuring tape from the hardware store. Emphasis on soft, friend. A soft measuring tape (or tailor’s tape) is designed to be super flexible so you can loop it around your body easily and THAT is juuuust what you need. 

 ”Stand in front of a mirror while measuring so that you can ensure that the measuring tape is level. If it’s too high or too low, you’re not going to get an accurate read.  Let it be snug.” – Jennifer.


Step 2: Discover your band size.

how to measure your band size bra blogilates

For this step, you need your boobs to be relaxed and not pushed up in any way so you have 2 options: go braless or, make sure you’re wearing a non-push-up/non-supportive bra. 

Part 1:Wrap the measuring tape around your torso and place it directly under your bust (directly underneath your boobs).

Remember what Jennifer said: the tape should be level and snug (not tight).

Part 2: Got your number? Perfect. Now… this part is important:

Is the number even? If so, add 4 inches to your measurement. 

Is the number odd? If so, add 5 inches to your measurement. 

For example, my measurement read 39.” 

39 + 5 = 44

My band size is 44. 


Step 3: Discover your bust measurement

how to measure your bra size measure bust blogilates

Part 1: Wrap the measuring tape around your back, under your arms, and around the fullest part of your chest.

Remember: level and snug (not tight).

Part 2: Got your measurement? Beautiful. Now round to the nearest whole number. 


Step 4: Find your cup size

how to measure bra cup size blogilates

Bust size – Band size = Bra Size 

I was never good at math so, I’ll keep this simple for you. 

Part 1: Subtract your measurement from Step 1 (band size) from your measurement from Step 2 (bust size). 

Part 2: Take your answer, and refer to the size chart above to calculate your cup size. 

Ok, I’ll go first. My bust size is 46 and my band size 44. Let’s do this. 

46-44 = 2 inches 

This means my cup size is a B. I am a 44B. 

Friend… we did it. We found our bra size!!!

Myth Bust-ers

Let’s be real: there is NOTHINGGGGG more frustrating than finding something super cute like to the point where you’re literally itching to add it to your cart just to find out… it’s sold out in your size. 

True or false: Sister sizing exists with bras (aka your boobs can fit into different cup sizes).


“You actually can size up or down depending on what is comfortable for you and what works best for your body.” – Jennifer

When Jennifer told me this, I was sooo happy. A rule of thumb is to move up or down by 1 band or cup size depending on the brand. 

“Every brand has their own “fit” it can be really trial and error for you to find what works best for you.” – Jennifer 

So basically, If I’m doing what I do best (cough, shopping) and a specific bra isn’t comfortable on my body because of the cut and I grabbed my normal size (44B), my next move would be to try a 46A for more room or, a 42C for less room. 

Ok bra knowledge!!! 

Knowledge is Power

The edu is poking through, no pun intended. I don’t know about you guys but there’s something so empowering about knowing how to shop for YOUR body. 

Personally, being plus size, there is a certain amount of trauma that follows me through the mall:

Will my size be available?

Is there even anything cute in my size? Nope, the store doesn’t carry it. 

YES! The button is clasped….but can I sit and function in this? 

Don’t get me wrong, it’s great to have certain tried-and-true products under my belt that I can be truly comfortable in and also FEEL good in. But as they say, knowledge is power – knowing my body and what works for MY specific lumps, bumps, and curves is so so important when trying to reclaim that traumatic story. That’s something I not only want to experience, but I want for you too. You deserve it ❤️

Alright, now that I finally know bra size, guys I need recs. What’s your favorite comfy bra?

11 thoughts on “How Do You Measure Your Bra Size at Home? Let’s Learn Together.”

There are 11 comments posted by our users.

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  1. Michaela says:

    Answering your call for comfy bras: I have always worn Warners bras and I don’t think I would ever want anything else as primary, everyday bra. I know they aren’t particularly stylish or “sexy”, but the way I see it, that just means that they focus on what’s important: being a good bra! Mine are really comfy, and I’ve had them for years. They’re a little stretched out at this point and I should probably replace them, but the fact that they have lasted so long really attests to their durability and quality.

  2. Valerie says:

    This method NEVER works for me. My band size would be 38(34+4). That size rides way up in the back, plus I can get more than one finger under a 34 size band so I could fit my whole fist uner a 38. I don’t trust this information.

    1. Mina says:

      Same for me. According to this, my bra size would be 32C, but in that size, the band is always way too loose and sliding up, and the cups are way to small and spill out. Instead of adding 4 inches to the band size, I round to the nearest even number and then take the difference. The most well-fitting bras I own (no sliding, no spilling, and no digging in) are size 28DDDD, sometimes 30DDD. I measure 28″ around and 34″ at the fullest part. And I’m not big at all – nothing impressive to brag about here – very mid-sized. The idea of a D cup sounds humongous to most people, but I think it’s because of this adding 4 inches misconception.

  3. Vilma P. says:

    This is incredibly helpful. I can’t to go home and find out what my true size actually is 🙂

  4. H says:

    The is is wrong. Never +4 it makes the band way too big. Go with you band and bust measurements as your starting size. You can adjust accordingly.

  5. Abby says:

    So I did those measurements and they tell me I am a AA cup. I’ve never been a AA cup in my life. Perhaps these measurements work for other people, but this is not something I can use.

    1. Kay says:

      I’m thinking the same thing! I’m usually at least a D cup of not DD and it’s got me all the way down on an A. I would never fit in an A cup in my life!

  6. Ulli says:

    Please please please DON’T use the +4 method! It’s an outdated technic from a time when bra fabric didn’t stretch. Look up theirishbralady in instagram or the abrathatfits . org calculator.
    Let’s say someone has a 32 underbust and a 36 bust, where should those inches go in an aa cup with a band that is as big as the whole bust? With the above measurements the starting size for trying bras should be a 40G.

  7. Kristin says:

    I’m a little confused. By the time I add 5 to the band size measurement, I’m at 38. 36 (bust size)-38=-2. I’ve been wearing a 34B for years.

  8. Lauren says:

    Yeah, this did not work for me. Because of nursing for so many years, my boobs are saggy but still a lot in there, so every time I did this test it says I’m an A cup. I’m really a DD.

  9. Bri says:

    Please stop with the matrix sizing and +4 method. It’s so wrong and leads to so many busty women living in pain for years. Check out A Bra That Fits of Facebook or Reddit. Your band size should match your underbust measurement, adding only one inch of your an odd number (so 31in would go up to a 32). A 39in underbust and 46in over bust would be a 40DDD. There is no way a 44 band will have only one finger of space. I’ve tried on a band one size too big for me and it didn’t support me. Your support should come from the band. It should stay in place and not ride up or fall down, even without adjusting the straps to get it level. For the love of everything, please STOP this insanity and stop lying to women. Average cup size is like a DD. I’m a 34J. It’s not that huge.