
It’s impossible not to feel totally girly in a beautiful bra… but did you know there’s a good chance you’re wearing the WRONG size bra?
Don’t feel bad – 80% of bra wearers are too! This includes crossdressers and transgender women, as well as cisgender (genetic) women.
Wearing the correct bra size is critical. Bras that don’t fit right are uncomfortable and look bad under your clothes.
In this blog post, I’ll show you how to find your correct MTF bra size so you can choose the perfect bra for your female transformation.
How to Determine Your Correct Bra Size – Without Breast Forms

Determining your correct bra size begins with a choice: Will you be wearing breast forms with the bra?
In this section, I’ll explain how to find the correct bra size for your ACTUAL breasts (without breast forms). In the section below, I’ll show you how to find the correct bra size if you wear breast forms.
Step 1: Measure your band size
- Wear a non-padded bra that fits well.
- Wrap a soft measuring tape snugly around your ribcage, directly under your bust.
- Ensure the tape is parallel to the floor and not too tight.
- Round the measurement to the nearest even number.
- This is your BAND SIZE.
Step 2: Measure your bust size
- Keeping the tape measure snug, wrap it around the fullest part of your bust.
- Make sure the tape is parallel to the floor and not squishing your breast tissue.
- This measurement is your BUST SIZE.
Step 3: Calculate your cup size
- Subtract your band size (from Step 1) from your bust size (from Step 2).
- Check the chart below to determine your cup size. (Each inch of difference corresponds to one cup size.)
| If The Difference Is: | Your Cup Size Is: |
| 0″-1/2″ (1.3 cm) | AA |
| 1/2″- 1″ (2.6 cm) | A |
| 2″ (5.1 cm) | B |
| 3″ (7.6 cm) | C |
| 4″ (10.2 cm) | D |
| 5″ (12.7 cm) | DD or E |
| 6″ (15.2 cm) | DDD or F |
| 7″ (17.8 cm) | G |
| 8″ (20.3 cm) | H |
| 9” (22.9 cm) | I |
| 10″ (25.4 cm) | J |
For example, if your band size is 40” and your bust size is 44”, the difference is 4”. That would make you a D cup.
Your bra size is a combination of your band size and your cup size. (Bra size = band size + cup size) In this case, your bra size would be a 40D.
IMPORTANT: This size should be considered a starting point, since sizing varies from bra to bra. If possible, try on the actual bra before you buy.
How to Determine Your Correct Bra Size – With Breast Forms

If you wear breast forms, the process for finding your bra size is a bit different. Here’s how to do it:
Step 1: Measure your band size
(Note: These instructions are the same as above, but I’ll repeat them here.)
- Wear a non-padded bra that fits well.
- Wrap a soft measuring tape snugly around your ribcage, directly under your bust.
- Ensure the tape is parallel to the floor and not too tight.
- Round the measurement to the nearest even number.
- This is your BAND SIZE.
Step 2: Determine your ideal cup size
The next step is to determine the cup size you want to achieve. This should be a size that’s proportionate to your body: Not too big and not too small.
Generally speaking, the larger your body frame is, the larger your cup size should be.
Here are some guidelines:
- Choose an B or C cup if you have a small frame.
- Choose a C or D cup if you have a medium frame.
- Choose a D cup or larger if you have a large frame.
Once you know your correct band size and desired cup size, you can purchase the proper bra and breast forms.
For example, if your band size is 40 and you desire to be a D cup, you’d simply purchase a 40D bra and D cup breast forms.
Easy right? 🙂
What About Other Bra Fitting Methods?
There are a couple other bra fitting methods out there. However, the instructions I shared in this blog post are considered the most accurate method.
Some guides will tell you to add 4–5 inches to your band measurement. That’s outdated advice from when bras were made differently.
Modern bras are sized much closer to your actual ribcage measurement – adding inches will give you a band that’s too loose.
You may also see the “armpit method,” which involves measuring above the bust, under the armpits. (It’s the method Victoria’s Secret uses.)
While the armpit method can work, it often leads to a larger band size and a poor fit. For that reason, I recommend the ribcage method described above.
Finding A Bra That Fits

Knowing your correct bra size is one thing. Actually FINDING that bra is another.
Unfortunately, it’s not always easy to find bras outside the standard size range. Here are some sites that carry a large range of bra sizes:
- Barenecessities.com – Bare Necessities offers a huge selection of bras, including plus size bras with smaller cup sizes. (Perfect for crossdressers and trans women who don’t wear breast forms.)
- HerRoom.com – Her Room is another large lingerie site that stocks hard to find sizes. They offer band sizes up to 58, so there’s a bra for almost everybody.
Another option is to purchase a bra extender. A bra extender is an elasticized piece of fabric that hooks onto the back of your bra. It can add 1-3 inches to the bra band, so it’s a great solution for bras that are too tight.

So there you are, girlfriend! Everything you need to know about finding your correct bra size.
As always, I’d love to hear your thoughts! Please leave me your comments below. And if you have any beautiful bra pics, don’t forget to include them!
Love,
Lucille

P.S. Looking for a natural way to fill out your bra? Check out The Flat to Femme Program to discover an effective and proven approach to male to female breast enhancement.





I am a 36 B or 34 C….I went and got meassure at Victoria Secret
I was measuring wrong. I will re measure today and see what I come up with. Thanks sweety. i was meassuring under my breasts instead of above my breasts. OMG.
I was just going to look up my breast size. 42/44 makes me a 42B. The doc says I’ve got a year before I need in plants. I’m looking for 42C
Thanks for reading my mind. Not a easy think to do, since it is so scrambled.
If you drop a band size you go up a cup size. Say for me I am a 36 B or 34 C
I feel comfortable wearing a 34c size bra
My upper fram is probably a medium according to your post.
A 34c size bust is just the right size for me and doesn’t make it look like I’m trying to flaunt my breasts
I do wear breast forms so I can have a natural looking set of breasts and it’s hard to tell if they are real or not
Thanks for the tip on finding the right bra to wear and I was suprised to find out that I was already wearing the perfect bra
I have grown my own natural breasts without chemicals. The tape says that I should be a C, but as my breasts are slightly pointy without a broad base, I get a better fit with B cups. My problem is that I have male shoulders and wide set breasts, so the shoulder straps do not usually hold me together enough for a nice ‘V’ cleavage. I get by fine with bras, but have to be careful how I move wearing one piece swimwear without falling out the sides! How embarrassing!
Sorry but that formula is totally wrong.
I have been on HRT going on two years now and I am 40″ above my breast and 47″ around my breast.
According to that formula I would need a 40G bra. A 40G? OMG that’s huge lmao.
I wear a 40C or 40D depending on maker.
I tried every 44 but decided on a 42 B, Im between a B cup and a C cup
I feel right as a 36C girl.
I would say I’m in the medium range size.
I feel right as a 36C girl.
I would say I’m in the medium range size.