Let’s talk for a minute about sweaters. I am a sweater knitter, through and through. A pair of socks can take me a month, but I’ll whip through a sweater in two weeks, no problem. And many of you are scared to make a sweater, because you’re not sure if it will fit right, or how to make it fit right, so I’m hoping to help you take the sweater plunge, here.

Sweaters are built on measurements for some key areas of the body:

Bust (blue)
Natural waist (pink)
High hip (orange)
Arm circumference (green)
Length from underarm to end of garment
Sleeve depth (length from underarm to shoulder)

And if you are lucky enough to be shaped like my illustration here, you are probably okay to just measure, find the closest size, go forth and knit. Most sweaters are based on the “average” female body type, which is the hourglass shown above. But we all know there a zillion different body types. I’m a pear, through and through. I can get bigger or smaller, but I’m always a pear. If I apply the same measurements, in the same places, to my own body, the sweater will not fit. Witness exhibit A:

First, some definitions:
Bust – this is the total circumference around the fullest part of your bust. NOT your bra band size.
Natural waist – this is the circumference around the narrowest part of your waist; for most people this is about 2-3 inches above your belly button. If you are measuring at or below your belly button, you are measuring too low and need to move up. Many people have trouble with this due to prevailing negative body image, so as a guideline I’ll share – I typically wear a size 12 in pants and my “natural waist” is 31”. Do I have larger areas around my middle? Absolutely. But knowing that won’t help me fit my sweater.
High hip – another tricky one! This is the circumference around your hips at the very top of your pelvic bones – not the largest place around your rear end, which is the traditional “hip” measurement. The high hip is typically where you want a sweater to fall, so unless you are knitting a coat or tunic-length garment, you should use your “high hip” measurement for your hip measurement. For me this is a huge difference – my hip measurement is about 44” but my high hip is only 38”. If I knit my sweaters to be 44” wide, they’d fit me terribly, being 6+ inches too large at the hem.
Arm circumference – this is the circumference around the largest part of your upper arm, usually just below your shoulder.

Here are where the bust, waist, and hip measurements might fall on different types of bodies.

Now that you’ve located the correct locations on your body for your bust, natural waist, and high hip, you’ll want to take some length measurements. I am only 5’4” (about 1.6 meters for the metric folks), and still find most patterns as written to be woefully short. And, as shown in the illustration above, different body types mean the waistlines and bustlines may fall at different places than the pattern assumes. First, measure the length straight up and down from your underarm to your preferred sweater hemline. Then, measure the length in the same manner from the fullest point of your bust to your natural waist, and again from your natural waist to your preferred hemline.

This seems like a lot of work, but you only have to do it once and then you’re ready to knit sweaters that fit. So, you’ve written down all your measurements, now what?

Most patterns have a schematic included, and are general sized by bust measurement. Locate the appropriate size based on your bust measurement on the schematic and check the waist and hip circumferences for those sizes. If they match your own, you’re good to go. If not, you’ll want to adjust the pattern accordingly, or your sweater will not fit you (and then you’ll never wear it – how sad would that be?).

For me, this is what I know about my body – my bust is about 35”, and most patterns have a hip measurement for this size of 35”. I need 38”, so I multiply 38 (or 19, if knitting flat) by the number of stitches per inch. This is the number of stitches I need to have at the bottom of the sweater.

My natural waist is 31” and is only about 6” from my hemline. I like to have a bit of positive ease around my middle, so I add an inch, and multiply 32 (or 16 if knitting flat) by the number of stitches per inch. This is the number of stitches I need to have at the waist of my sweater, which should be about 6” from the hemline and 9” from the underarm.

Now when I start knitting the sweater, I can simply substitute these numbers in for the pattern instructions. If the number of stitches you need for the waist is fewer than in the pattern, you’ll need to do more decreases than the pattern calls for, and vice versa if it’s larger. The same for the hip area. And if the pattern says to knit to a length that is less than your actual desired length, you just substitute in your own length measurement. Patterns that don’t have schematics are harder, but you can get the measurements in the pattern instructions my multiplying the given stitch or row counts by the given gauge.

And then there is the issue of sleeves. My arms are 13”, about 1” bigger than the fit size for most patterns in my size. I add these extra stitches accordingly, which can be tricky to incorporate into sleeve cap shaping if you’re not knitting a raglan. Typically when making sleeves bigger than the pattern calls for when knitting a sweater in pieces, you’ll bind off more stitches to begin sleeve cap shaping and decrease more frequently as well. If this is the first time you’re trying to modify a pattern to fit, I would start with a raglan (bottom up or top down) so you get a better idea of the process.