Dear Andrea,
The sweater pattern I want to use is written for small finished bust, (36") only. The designer says, "if you were to add 4-6 stitches it would work for larger sizes." This doesn't seem adequate to me. The yarn knits up 2 sts per inch and 3.1 rows per inch on # 11 needles. I would like to make it 40" finished. Is there a nifty formula for adding stitches based on body measurements, type of yarn, gauge, etc.
If you know of a good knit sizing & design book, could you please pass that along also?
Thanks so much for your time,
Joy
Dear Joy,
Yes! You can "re-formulate " a pattern to suit your size. I had intentions of writing a post like this, so thanks for asking!
Let's start with the basic principle of using gauge to calculate the stitches and rows needed for whatever measurements.
For calculating stitches for width:
sts per inch x width'= sts for width
2 sts per inch x 40"= 80 sts
The same can be said for calculating rows for length:
rows per inch x length"= rows for length
3.1 per inch x 18"= 56 rows (round up decimals)
The reverse can also be done to figure out the the width or length in stitches or rows given.
sts / sts per inch= width"
99 sts / 5.5 sts per inch= 18"
rows / rows per inch= length"
150 rows / 7.5= 20"
But that's not all! You may need to add ease to your pattern. Otherwise it will be skin-tight.
Explaining Ease
Ease is extra width added. It can vary according to what kind of fit you desire and yarn thickness. For bulky yarns, add 2-4" ease all around. The reason being that thicker yarns knit up thicker, but also tighter in circumference. What this means is that if you used the same measurements from a pattern for a light weight sweater and substituted it for a bulky one, you might find it too tight around the body.
For making a larger size, it is not just a matter of adding width to a pattern. Body length is also important. On average, you could add increments of 1" from the size you are grading up from. So if you are working from a size 36 pattern, a size 40 pattern should be 2" longer. Length is also added to the armholes and sleeve cap height. Usually in increments of 1/2-1" per size. The same goes for sleeve length. Since you are customizing the pattern for yourself, be sure to measure yourself and tailor it to your own needs!
For your pattern, I would figure out just how much ease was added to the pattern. If the pattern is for size 36, and it says to cast on 39 sts for the front and back pieces, then I would do the calculations for 36" without ease to figure how much was added. Divide the bust measurement in 2 to get the width of the front and back pieces, 18". Multiply that by 2 sts per inch, which is 36 sts. Calculate the difference, which is 3 sts, 1 1/2" on front and back pieces, which is 3" all around ease. So whatever measurements I use for the body width, I will add the extra 3 sts for ease. So for example, a size 40, I would cast on 43 sts.
Because of my background in fashion design, it was easy for me to pick up the concept of working out sizing in knitwear (though, it's
not my favorite thing to do!). I have to admit that I don't have many knitting books. The one book I tend to go to is
Vogue Knitting, which has a section on designing your own knits. The book I recently
reviewed , also explains the subject of re-gauging a pattern, if that is all you're after. I did a search on books for knitwear design and found
these.
I truly believe that knowledge is power; and passing this on to other fellow knitters can give them the freedom to knit whatever they want with confidence. Isn't that what it's all about anyways?
Happy Knitting!
Andrea