
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.





This is a great article. Very helpful! I was wondering if you could do one about panties. Which are the best for tucking, or what brand has a wider crotch, etc.
This would be very helpful.
Thank you!!!
so many ladies are wearing the bra and covering only nipple are of the breasts and other parts of the breasts are outside.This is the correct way to wear the bra or we have to cover full breasts?
Hi Lucille,
Being a pensioner I have to purchase budget bras. I have a big chest and never wear any padding except for what may be in the bra itself. I generally go for a 14c (Aussie size) and need an extender except in one case. A 16c would be better, but the cups are too big and a 16B’s cups aren’t flattering.
This is a rare web cam I took in December last year. My boobs are cuurtesy of Flat 2 Fem, the right dress and bra also helps enormously.
Whoops, my post was sent before adding the pic. here it is.
“Demmy”…”Sweetie, You Look Fantastic”…”You Are One Hot, Sexy Girl” !
Dummy, you look absolutely fabulous. Well done you.
Heather (UK)
I guess I must be one of the 20% that picks them right I used that way to find my bra size I could not find the right waist size so I bought extenders so they were not tight it’s surprising that I was able to find one that I consider to be my favorite love it only hope that I can find another one like it after the flat to femme program gets them to the size I am aiming for
I am a b cup naturally thanks to your tip on phytoestrogens(they really work!!!). My question is when I don’t wear a bra, what can I do to hide my nipples? They protrude often.
I have found the 34C size bra is my best choice for dressing, as they are tight enough to hold the forms from wandering when moving about. I have tried the “aah” bra and the “genie” bra and like them. I have purchased the medium size and can wear them under my work clothes, as they don’t show in guy mode, or use it to hold my breast forms when dressed en femme. Also they do not show any seams when wearing tight t-shirts or blouses. They may not be everybody’s choice for everyday wear or support, but they are worth a try.
I found getting a proper bra fitting at my local Lane Bryant store was beneficial in finding my proper size but also a very feminine affirming experience. One I recommend to all ladies.
Searching for and buying a bra usually has been a big thing for me but lately I have worn t-shirts with the neck cut out and no bra. Finally I have reached an adequate point where if someone wasn’t quite sure then their question is quickly answered. The t-shirt, short of being wet, is expressive enough. Such expressions is not my usual way and I think after I get use to the change I will resort back to the just blend in me but for now at least some part of me shows off to the world whom I really wish to be.