I hear from lots of women with breasts smaller than B who are totally frustrated when shopping for bras. If you a B-cup or larger, and reading this with a smirk, thinking – what do they have to worry about – let me enlighten you. A-cups and smaller sizes can be affected by gravity and the aging process, just as much as larger breasts, and have equal needs for modesty and adequate coverage. But, just like the lack of bra cups larger than DDD, there is a distinct lack of bras available in sizes A, AA and AAA. What’s that? You didn’t know there was anything smaller than A? Pull up a chair, grasshopper, and let me explain…
By definition, bra cup sizes are found by calculating the difference between the high bust measurement and the full bust measurement. Each inch of difference is assigned a letter, with 1” being the standard increment used in North America and most western countries. So, on this side of the pond, 1” of difference is called A cup, 2” is B, 3” is C and 4” is D. OK so far?
So what happens when we go down in size? AA is considered to be a difference of 1/2”-1”, while AAA is considered to be 0-1/2” difference. There is no smaller size than AAA, since we can’t go lower than a difference of 0”. So, while all the other sizes move in increments of 1”, the petite sizes (as they are often called) move in 1/2” increments.
Now before we go on, I know you are going to go surfing and find a few bras out there in small sizes but often, those bras are padded, sometimes ridiculously so. Do all manufacturers think that A-cups automatically want or need padded bras? The A-cups I’ve met are quite happy with their size, and who can blame them? There are advantages to having small beasts, and this is purely as I see it:
You never have to worry about a blouse not fastening in the front
You can make a bra from virtually any fabric
You don’t have to worry about using industrial strength fabrics for support
You can make a bra from a small piece of fabric (a gal in my class at the monastery made the most incredible bra from a placemat size piece of Chinese brocade!)
Smaller bras use less elastic and channelling, saving you money in supplies
Smaller underwires are cheaper than larger ones.
You don’t have to hold on to your breasts as you run down the stairs
But let me explain the technical differences between cup sizes smaller than B. If you are making a bra for yourself, of someone you know with petite cups; or if you are designing for ready-to-wear, you need to know this.
Any cup size has a certain depth (known as the Bottom Cup Depth) and a certain diameter, which is known by the underwire number. Let’s look at the diameter for the moment. A 34B bra uses a #34 wire. Yes, I realize that some companies number their wires for the A-cup sizes, but just accept the fact that B-cups use #34 for now, so you see what I am driving at. A 34C uses one wire size up from the B, making the wire for a 34C a #36 wire, since wires run in even numbers. A 34A uses one size smaller than #34, making it #32. So, the diameter increases like shown on this chart found in my book for cross-grading underwires. If you’re the type of person to feel almost obsessed with finding patterns or logic in everything, you might enjoy the challenge of filling in the question marks below.
Done? If you are like 99.99% of my blog readers, you will have filled in the question marks as shown below. How did you do?
Don’t be giving yourself that gold star quite yet. This chart and the assumption that AA and AAA follow the “normal” pattern is incorrect. Ahhh….now pay attention!
A funny thing happens when the cup size is smaller than A, the wire size, in other words, the diameter of the breast, does not get any smaller. Put another way, a 34AA uses a #32 wire and so does a 34AAA! Likewise, a 36AA and 36 AAA use the same size wire as the 36A. All A, AA and AAA, stay the same diameter. Whatever wire size the A uses, so follow the AA and AAA. So here is the correct answer to the chart.
This shows up clearly in the drawing of the wires below. The AAA, AA and A are the same diameter, and the B and C are larger by 8.5 mm (.33″).
So, does this mean that A, AA and AAA are actually the same size everywhere? Not at all. Only the diameter of the wire remains the same. The difference is in the Bottom Cup Depth (BC), which is the distance from the wire line crease to the apex (nipple). In ready to wear, these are standardized from one company to the next.
If you could see the cups from the top down, the A, AA and AAA would look something like this drawing.
Notice the diameters are equal, as they should be. But the projection from the wall (which determines the BC depth) decreases as the sizes goes down. Some companies use 3/16” as this measurement, and some use 1/4”. Either way, it shows that the projection decreases.
If you have a bra pattern in an A, yet the cup is still a little baggy, but the wire size seems to be fine, you probably really need an AA. If it is a fair bit baggy, you’ll need to go to an AAA. Pin out what you need to get an idea of how much to take out. Here is the alteration that you need to do.
The dotted line is the new size and it would be moved down either 3/16” or 1/4” per size, depending on whether your fabric is rigid or stretch. It’s always best to make a sample to check it out.