Let’s be honest — bra sizing can feel like one of life’s great mysteries. Even people who’ve been wearing them for years often find themselves guessing. If you’ve ever bought one that looked perfect, only to find it pinched, gaped, or just didn’t feel right… you’re not alone.
For those of us creating or enhancing a feminine shape, finding a bra that fits comfortably and looks natural isn’t about following strict “rules.” It’s about understanding a few basics — and then shaping them (quite literally) to suit you.
1. Let’s start with the numbers: your band size
Bra sizes are written as a number and a letter, like 36C. The number represents your band size — that’s the measurement around your ribcage, just below your chest.
If you had natural breasts, you’d measure just under the tissue. Forthose who do not have natural breast tissue using breast forms or padding, that’s obviously not possible in quite the same way.
So instead, measure around your ribcage about 2” (5cm) below the nipple line.
If your measurement is an even number, that’s your band size (for example, 38” = band size 38).
If it’s an odd number, round it up to the next even size to ensure comfort — for example, 39” becomes 40”.
2. Understanding the letters: cup size
The letter represents the cup size (the difference between your band size and your full bust circumference)— in other words, how much space there is for the breast shape to fill.
Here’s a quick guide to what that means:
- 1"/2.5cm = A
- 2"/5.cm = B
- 3"/7.5cm = C
- 4"/10cm = D
- 5"/12.5cm = E
If the difference is not a whole number, so it might be 3.5" then that's when the double letter comes into the sizing. CC would be a difference of 3.5" between the bust and chest measurement.
Now you have an understanding of bra sizing, it's time to actually decide what size suits you and feels comfortable.
3. Finding your cup size in practice
Once you’ve decided on your band size, it’s time to experiment with cup shape. Your choice of bra has a significant impact here, but I will do a seperate post on Types of Bra. (Watch this Space)
There’s no such thing as “average.” Some people prefer a C cup for a balanced, natural look, while others love a more dramatic curve — and that’s perfectly fine.
As a very loose guide:
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If your band size is 38” (97cm) or below, a C cup breast form gives a natural, in-proportion shape.
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If your band size is above 38”, you might find a D cup or larger feels more balanced with your frame.
Remember, these are just starting points — not rules. What matters most is how you feel when you look in the mirror.
4. A quick way to check your size
If you’re using breast forms or padding:
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Put on a bra that feels comfortable.
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Adjust or pack the bust area until you like your reflection — until it feels “right.”
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Measure around the fullest part of your bust (across the nipples, including any forms).
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Subtract your band size measurement from this number.
The difference in inches will tell you your cup size.
For example:
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Ribcage (band) = 40” / 102cm
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Full bust = 44” / 112cm
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Difference = 4” / 10cm → that’s about a D cup.
5. Getting the look you love
The truth is, there’s no wrong size — only what feels best on you. Some people love the gentle curve of a smaller cup, others enjoy the fuller, more glamorous silhouette of a larger one.
It’s all about balance and confidence. The most flattering size is the one that feels comfortable, looks natural for your frame, and makes you smile when you catch your reflection.
If you’re just starting out, play around with temporary padding before investing in breast forms (and yes, you guessed it, there is another post coming about options of breast forms). Use soft materials or inserts to experiment until you find the proportions you like best.
A point to consider is that, commercial clothing manufactures work on the assumption that sizes up to a UK 16 have a bust size upto a C cup. From a UK 16 upwards, they presume the cup size is going to be proportionally larger. So if you're considering going for a 38EE size, which I'm sure bra manufacturers do make, finding clothes that fit your body shape might be a bit of a challenge.
6. Final thoughts
Finding your ideal bra size isn’t just about numbers — it’s about discovery.
It’s one of those small but empowering steps that can help you feel more you.
So take your time, measure carefully, and most of all — have fun with it.
Because when it fits right, everything else just feels a little more fabulous.