
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 have been a 36B for years, but I would love to graduate to a C if that were possible. I started wearing them as support for hiking, as there was too much chafing going on with my nips otherwise. It gets embarrassing if you have to hold your chest in!
Now that I have received my “official” letter for going full-femme, I am looking forward to doing that. These tips are worth their weight in gold for those who have not been raised female. Many thanks!
Lucille,
Thank you so much for dealing with bra sizes, because I am comfortable with a loose size 38B, however according to your guidelines I could wear 34B, however the ones I recently purchased were tight enough to turn into strapless, by removing the straps for the effect it has.
Need I also say, that your hypnosis videos are an inspiration, thanks,
Love, Diane.
Im a 42B but am a bit fat so I need to make them a D
Thanks for the guide, I myself measure a 40B but like how a 38B fits me not to tight not to lose and holds my girls nicely. I have measured myself several different times and always hope my girls will grow a little more but for now they are stay at 38B I think it because of the weight lose. I also do not like breast forms I like being all natural so I use the add a cup bras when I need a little extra up top to fill out a dress or blouse.
“Lacy”…”WOW”…That Is Such A Pretty Bra…It Looks Fantastic On You…SO SEXY !
Extremely informative for me, as ever, Lucille. I love the look and feel (on a hanger) of a pretty pink lace bra. I have been wearing a 38B bustenhalter (sizing arrived at by estimate), although I have suffered backache after having it on over a long period. I am upgrading to a 38D. I cannot wait until next week’s.
After this blog post my bra size was re-confirmed at a 38B. Actually my band size is 37 and if since there are more choices in stores at 36B, sometimes I get one.
Bra size is very important in making sure your clothes look good and like Lucille says, all types of women often make the wrong choices.
I love lingerie and particularly bras, and I agree it’s hard to feel really feminine without a nice bra. But I find it difficult to find the right size.
Laurie and Cassandra hit it on the head when they stated different brands seem to have different sizes.
Using your guidelines and my breast forms I’d wear a 36D bra. But every time I purchase that size, the band size is too tight so I wear a 38D. Recently I purchased two 38D bras from different manufacturers. The first fit nicely. The second was so tight I could hardly breathe and the cups were so huge even my breast forms got lost.
Another comment that I can attest to is that even with my bra straps fully extended I feel like they should be longer.
Lucille,
Thanks so much for the tips on selecting the right bra. I’ve been taking medication for the past few months and have moved from a 38A to a nicely rounded 38B cup size. There’s nothing more girly than having lovely feminine breasts of your own. Your suggestions are right on target. I’m waiting for your next posting. I need a little more information on the best style to both support and flatter my breasts as they keep developing.
Many thanks for all your columns and blogs. We aspiring girls do appreciate your interest, acceptance and support for us.