The magic formula to knit any model with any yarn!

Whether it's knitting or crocheting, the question of dimensions and sizes is essential for knitting or crocheting a garment that will fit you after spending hours knitting or crocheting it. What could be more frustrating than finishing a knit and realizing it's too small, too big, with a too short armhole, ....

There is a little magic formula that allows you to find out how to knit any pattern with any thread!

A little theory

Firstly, a golden rule in knitting or crocheting must be emphasized.

For a given size, if you use a thinner yarn than the model used, you will have a finished garment smaller than the dimensions given by the model. Conversely, if you use a thicker yarn, you will have a finished garment larger.

In this picture, the sweater in the middle corresponds to the garment as the model explains in the instructions in the size you want. The sweaters on the left and right are the results you will get if you use a thinner or thicker yarn and you knit the model in the size you want...

The magic formula

In order to apply this famous formula, two values must be known:

• The width value of the model's sample (i.e., X stitches for 10 cm.)
• The width value of your sample (i.e., Y stitches for 10 cm.)

If X = Y, you have nothing to do here and you can directly cast on the number of stitches that corresponds to your size!

For the others, the following formula must be applied:

((Y - X) / X) x 100 = error percentage of your sample

Once you have this figure, you can refer to the model's size chart and find the size corresponding to your error percentage.

Let me explain because this can be a bit obscure. When looking at a size chart for a model, we usually find the finished garment dimensions. Personally, this is the value I most often work with, it makes more sense than S, M, L, and other 36, 38, .... whose canons vary depending on the country or brand.

In the finished garment dimensions, I look for the size that will best match my sample and my size.

Example

For my example, I will use the model Trescao Jumper which is super and free on Ravelry. This allows you to also do the exercise on your side.

I have a chest circumference of 95 cm. and I would like it to be a bit fitted but not too much, so I would prefer to knit size 100.

In this model, the sample is 21 stitches for 10 centimeters but my sample is 23 stitches for 10 centimeters. So I apply the magic formula ((23 - 21) / 21) x 100 = 9.5 %

If I knit size 100 with this yarn, I will end up with a sweater 9.5 % smaller, meaning a sweater that will measure 90.5 cm in chest circumference. My sweater will be too small and I will never wear it. So I am going to look for a size approximately 10% larger than the size 100 of the model. Here the calculation is simple 10% of 100 = 110, I will knit size 110 to have a sweater that will measure approximately 100 cm in chest circumference.

What about the length?

From the start of this article, I only talk about the width of the samples. That's intended! I never look at the length of the sample, i.e. the number of rows for 10 centimeters. Indeed, to get the desired length, you just have to knit more or less rows compared to the model's instructions.

Your favorite sweater measures 30 cm from the base of the armholes to the bottom of the sweater? Then knit 30 cm even if the pattern states 33 ;) The designer of the model will not come to check if you have correctly knitted his model, however you risk not wearing your sweater because you find it too long compared to your favorite so perfect sweater!

Never forget, you are creating your own garment. You are the artist! It's your turn to play!