Disclaimer: I’m only covering raglan shaping in this post, but I am working on another post that is a companion to both this and the bust dart, and is essentially a bust dart located in the upper bust that should (theoretically) work with any construction. I haven’t attempted it in a garment yet, and I prefer to before I make a post about it, just to be sure it actually works.
Disclaimer 2: as with the bust dart post, this is going to seem like A Lot, but it’s really not. I timed myself doing the math from this post for the Flax sweater, and it took me a total of 7 minutes, and that included taking the measurements.
What is a full bust adjustment (henceforth FBA)?
A FBA is an adjustment commonly made in sewing to accommodate a larger bust compared to the shoulders.
Why are FBA’s necessary?
When a designer grades a pattern, they are typically grading for around a C cup. Sizing standards tend to be based on “averages” which are rarely accurate to the actual sizes of real human beings, and the bust size is no exception.
When you wear a D cup or higher, and pick your sweater size based off of full bust measurement, often you’re going to be knitting a size that is too large in the shoulder scye and upper bust to accommodate your full bust measurement. And when the shoulders don’t fit, the whole garment can appear ill-fitting, no matter how well the bust, waist, and hips fit. This is especially so if you have narrow shoulders.
So, let’s use my own measurements and the Craft Yarn Council’s standards as an example. Using my full bust measurement, as most patterns have you pick your size by, I’m a 2X-3X depending on the time of month. (My bust fluctuates from 49-52″.) The shoulder to shoulder measurement listed by the Craft Yarn Council for those sizes is 18″.
But my actual shoulder to shoulder measurement is 15″. That means that a pattern with 0″ of ease based on this size guide that will fit my full bust will have 3″ of positive ease in the shoulders. Ysolda’s size chart (which is significantly better than CYC’s) is much closer to my actual measurements, but they still have 1.75″-2″positive ease.
That difference isn’t such a big deal in a garment with tons of positive ease, or in a drop shoulder top, but in a fitted garment that difference can lead to a top that is baggy at the shoulders, or to bunching in the armpits.
That’s where a FBA comes in.
The short version of it is that you knit the size that will fit your neck/shoulder/upper bust measurement, and increase in the front before the full bust. This will give you more stitches in the front than in the back, since you will need more fabric for your bust than your back.
I’m going to detail the formula I use for a top down raglan. I’ve never tried to adjust this formula for any other kind of construction, but it should be possible. Just don’t quote me on that when it fails. 😂
And of course, any texture patterns or colorwork will complicate the method I’m outlining.
Full disclosure: there are multiple ways to make a FBA to your garment – this is just the method I use. I’m currently testing the Beaudelaire Top for Melissa of Skeinanigans, and she has included a FBA to the instructions that uses a different method of choosing your size than the one I’ve always used. If a FBA is something you need, you might want to pick that pattern up when it’s released to learn her method – it might well fit you better!
As with the bust darts, there are some measurements to take. You’ll need to know your upper bust measurement (UBM), and your full bust measurement (FBM). You’ll want your upper arm measurement handy, too, because you might need to adjust for that as well. You’ll also need to know your stitch and row gauge per inch. I’ll be using my own measurements as an example throughout.
First: a note on ease. It is very important to add whatever intended ease there is into this measurement. If the size you pick based off of your UBM has 2″ of positive ease, make sure you add 2″ to your FBM or you’ll end up with 0″ ease at the full bust, which probably isn’t what you intended going into this garment.
Measurements in hand, let’s get going!
The first thing to know is that you won’t be casting on the size for your full bust measurement, but rather for your upper bust measurement. Choose your size with your upper bust measurement in mind, and jot down the ease of the size you’ll be using to keep things consistent.
For the example in this post, I’ve written out the FBA for everyone’s favorite free sweater pattern – Flax by tincanknits.
My upper bust measurement is 41″, so for my sweater I would be casting on the size L (giving me 2″ of positive ease) and increasing to my full bust measurement + 2″ (52″). My upper arm measurement is 14″, so I won’t have to do any altering for sleeve size, since the sleeve circumference of the L-4XL is 21″, but if the sleeve circumference for the size you pick is smaller than your arm circumference, you’ll need to speed up the rate of increase for the sleeves, too.
The gauge for this pattern is 18 sts and 22 rounds/4 inches. Divide those numbers by 4 to get gauge/inch and we have 4.5 sts and 5.5 rows per inch. If you don’t get a whole number when figuring your gauge, go ahead and round to the nearest number. So for my example, my gauge is 5 sts and 6 rows per inch.
Let’s get to the math. The first thing you’re going to do is subtract your upper bust measurement plus from your full bust measurement to determine how many inches you’ll need to increase. (FBM – UBM = inches to increase)
My inches increased formula would be 50 – 41 = 9″.
The next step is to translate those measurements into stitches. To figure the total number of stitches to increase, multiply your inches to increase by your st/inch gauge. (Inches to increase x sts per inch = stitches to increase)
My stitches increased formula would be 9 x 5 = 45. Notice I have an odd number? Because I rounded up when determining sts/inch gauge, I’m going to subtract 1 stitch here to get the even number I need. I have 44 total stitches to increase.
In most raglan tops, you’ll have an increase row followed by a rest row. To create the FBA, some/all of those rest rows will have increases on the front. How many? There’s some more math.
Because we are only adding increases into the front, we’ll be adding 2 stitches to every FBA row. Take your number of stitches to increase, and divide by two. (Stitches increased / two = total FBA rows)
Using my example, my formula would be 44 / 2 = 22. I’ll need to replace 22 rest rows with the FBA increase row.
Uh oh. My size only has 20 repeats of the raglan shaping, which means there’s only 20 rest rows I can substitute with the FBA increase row. What now?
Never you fear, you have options.
Option 1: sneak four extra increases in by doubling the increases on a couple of rows. Not the option I would choose, but hey! It’s an option.
Option 2: split for sleeves as indicated for the size you cast on, and add a tiny dart afterwards. You could place this dart a stitch in from the sleeve separation (not the side seams – make sure to note how many you cast on for the underarm and knit a stitch past that before increasing) and increase by one stitch at each side every other row.
Option 3: Cast on more stitches at the underarm. If you’re only short 2 or 4 stitches, this could work. Just be sure that those extra stitches are on the front side of your side seam marker.
Option 4: If you don’t mind the armpit being a little deeper than written, you can continue working the raglan, omitting the increases at the back and arms.
This is my Tūmanako pullover. For the FBA in this top I did a combination of Option 3 and 4 after I had worked all the written repeats. I worked extra repeats without increasing at the sleeves and back, and cast on extra underarm stitches. Ignore my sloppy underarm. 😂
Alternatively, you could need fewer FBA increase rows than there are repeats. In that case, you would take the total number of written repeats – total increase rows needed to find out how many repeats you should work as written before substituting the rest row with the FBA increase row. In my Beaudelaire top, I worked two repeats with the rest rows before substituting in the increase rows.
And that’s really all there is to this method. I always combine a FBA with bust darts, and you can find my post on bust darts here.
There’s Tūmanako on. This method of FBA can look kind of odd off a body because of how it changes the appearance of the raglan, but it looks just fine on. I will say that this method can produce extra fabric in the underarms if your full bust point is low, which is why I’m working on that other post! Expect that at some point in the future. I’d like to work a top with that method to at least the full bust point before I write up the post, that way I can be sure the darts don’t look off.
As always, if you need help when working this method feel free to dm me on Instagram @masteryarnsmith or email me at firstname.lastname@example.org. I get back to everyone faster via those methods, so it’s the way to go.