A thread on boob math! AKA: How to pick your BA implant size

From the Blue Bird app

Lets do a thread on boob math! Also known as: How to pick a size for your breast implants, and why implants that SEEM really big actually aren't.

I see a lot of transfems agonizing over this size or that size of breast implant as they're gearing up for their top surgery, and SO MANY are worried about going "too big." Well, I got 900cc breast implants. I'm guessing that's bigger than you were thinking of going.

I'll bet you saw that picture and were super confused. 900cc's is like... stripperiffic, right? That's what you were always told, because cis women typically get 300-450cc implants when they go in. 900 is 2-3 times that size. Why don't they look bigger than they do?

Here's the math part.

The size of an implant is governed by the square-cube ratio. In a nutshell, it means whenever you square the surface area (the implant shell), you have to cube the volume of its filling. If you do much math, you get the point right now. If not, well…

The left graph is what happens when you square a number. The surface area. The right is when you cube it. The volume. The farther you go, the more rapidly the right one increases, and the farther it gets from the left.

Squared exponential growth and cubed exponential growth.

What this means in practice: Take a 450cc breast implant. It's going to project about 6cm from your chest, or 2.36 inches for us heathens on Imperial. But if you double the implant, to 900cc's, the radius is only about 7.5 cm, an increase in diameter of only 20%.

Let's go wild, and go all the way up to 1800cc implants. Surely that's insanely big, right? 9.5cm. Quadruple the volume of the implants and the radius only increases by about 60% from the "very normal" 450cc implants.

Square cube ratio. That's something, huh?

Tables showing the diameters of hemispheres of 450, 900, and 1800ccs.

DISCLAIMER: the math here is a little bit rough because with implants you can have a constant base radius which will alter the implant's projection. The numbers will be slightly off. The realities are the same. I can't do that with simple math engines.

This is why the most common regret in breast augmentation is not going bigger. I see people torn between 450cc and 550cc implants, and the difference SEEMS really big psychologically, but it's a *half a centimeter* of projection. So, keep this in mind when you're thinking about implant sizes: when you double the volume of the implant, you're only increasing its diameter by 20%.

And if you have a naturally large frame, like transfems often do, you may NEED lots of volume to be proportional.

ADENDUM: A little more specificity about choosing your implant size. I suggest throwing out cup sizing, and even CCs, as targets. Breasts are all about *ratios*--height, weight, frame size, breadth of the pectoral muscle--it's ultra individualized. Constant numbers will fail.

So, here's what's better:

1. Find a top surgeon who's comfortable working at "XL" sizes (anything more than 600cc's) and LOADS of experience in top surgery. You might not need this competence, but it's good to have. If people want, I can give info on my doc. (E/N: It’s Dr. Don Revis, of South Florida Plastic Surgery Associates. I am extremely satisfied with the quality of his work, and he treated me exactly the same way he treated his cis patients.)

2. Take naked pictures of your chest as it is from front, side, and 3/4 views. No bras, and especially nothing underwire, lined, or padded.

3. Find pictures--bikini shots are best--of someone whose boobs are closest to what you want. Again, no bras. We want the real look.

4. Send those pics to your surgeon and tell them "I want to look like that."

5. Let them choose the implant.

Yeah. That's right. Give up control of your implants.

Look, your doc is VASTLY more experienced than you. You don't walk into a fancy restaurant and tell the chef how to cook your dinner, do you? If you've chosen your doctor well, they're going to know more than you ever will about this.

Trust their judgment.