How to Work Out the Shaping Rates for Your Knitting Pattern in 4 Easy Steps
How long have you spent trying to manually work out the increase or decrease rates for your knitting pattern? Perhaps you’ve been tediously scribbling your sums down on paper or making individual charts to help you figure it out for each size in your range.
Back when I was starting out as a knitting pattern designer, this is exactly what I used to do. I kept a huge notebook of my workings out, but it took far too long, had too much room for error, and had to be redone every time I adjusted the numbers in my knitting pattern.
What if I told you that you could automate the whole process in a couple of minutes using a spreadsheet and four easy steps?
As much as it sounds too good to be true, this is exactly what I am going to teach you. By the end of this blog post, you’ll have everything you need to start calculating your shaping rates easily and efficiently at the click of a mouse.
Let’s begin!
Image description: photo of someone knitting with the words “How to Work Out the Shaping Rates for Your Knitting Pattern in 4 Easy Steps” on top of it
Easily and Efficiently Calculate Your Knitting Pattern’s Shaping Rates with the Magic Formula
The Magic Formula is one of the easiest ways to work out your knitting pattern’s shaping rates without having to resort to mental maths and creating individual charts for every size in your size range. It helps you to work out 1-2 sets of shaping rates to achieve your desired stitch count in the required number of rows/rounds.
When paired with a spreadsheet, you can use this fantastic equation to work out the shaping rates for one size and then simply drag the formulas across the rest of your size range to instantly have the shaping rates for them, too!
When I designed my first couple of patterns, I didn’t use spreadsheets, and all of my shaping rates were worked out, one by one, in my notebook. It took me ages! Using spreadsheets and the magic formula, I can design a 9-size sweater pattern in the time it took me to design a simple 3-size hat. It’s a game-changer!
Before you get started…
If you’d like to give the Magic Formula a try in your next pattern, you will need a spreadsheet and the following information:
The number of places you will be making increases or decreases in a single row or round
I call this a shaping point.
The number of stitches that you want to increase or decrease at every shaping point.
This is the total number of stitches you want to increase/decrease across the whole row or round, divided by the number of shaping points.
This will be called “a” in your formula.
The number of rows or rounds the shaping will be worked over.
This will be called “b” in your formula.
Once you’ve got a and b written out in your spreadsheet for every size in your range, you are ready to jump in.
How to Use The Magic Formula
Step 1
Divide b (the number of rows or round the shaping will be worked over) by a (the number of stitches you want to increase or decrease at every shaping point), then round this number down to a whole number. This number will be “c” in your formula.
For example, if I wanted to increase by 15 stitches at each shaping point over 70 rounds, I’d divide 70 by 15 and then round it down to a whole number, which in this case, means that c would be 4.
Rather than working this out mentally or with a calculator, I encourage you to use a spreadsheet instead. The formula you need is:
=ROUNDDOWN(b/a,0)
Make sure you replace b and a with the spreadsheet’s cell references for those numbers.
Step 2
Again, divide b by a, but this time, work out the remainder from this equation. This number will be “d” in your formula.
Keeping with my previous example, this would mean dividing 70 by 15 and working the remainder, which means that d is 10.
In a new cell in your spreadsheet, use the following formula to work out d:
=MOD(b,a)
Make sure you replace b and a with the spreadsheet’s cell references for those numbers.
If you get a result of 0, it means your equation doesn’t have a remainder, so you just have one shaping rate rather than two - nice and easy!
Step 3
Subtract d (the remainder from step 2) from a. The result will be “e” in your spreadsheet.
In my example, this means that I need to subtract 10 from 15 to work out that e is 5.
The spreadsheet formula for working out e is very simple, as you might imagine. Just use:
=a-d
Make sure you replace a and d with the spreadsheet’s cell references for those numbers.
Step 4
Add 1 to c (the whole number from step 1). The result will be f in your spreadsheet.
In my example, I need to add 1 to 4 to work out that f is 5.
And that’s it! You’re done!
Image description: photo of a woman working on a spreadsheet. The text reads: How to Work Out the Shaping Rates for Your Knitting Pattern in 4 Easy Steps
Interpreting Your Results
You now have the final results for c, d, e and f in your spreadsheet, which you will use to write your shaping rates.
Shaping Rate 1
Increase or decrease 1 at each shaping point every c rows or rounds e times.
If you didn’t get a remainder in step 2, shaping rate 1 will be your only shaping rate, so you don’t need to go any further than this.
If you did get a remainder, you will also use shaping rate 2 below.
Shaping Rate 2
Increase or decrease 1 at each shaping point every f rows or rounds d times.
To wrap up my example, here is what would my final shaping rates would be:
Increase 1 at each shaping point every 4 rounds 5 times, then every 5 rounds 10 times.
The way you choose to work these shaping rates comes down to your preference. More frequent shaping rates will create shallower angles, whilst less frequent will create steeper angles. Work the shaping rates in the order that creates the angle you need.
Checking Your Results
It can be reassuring to double-check your results, especially if you’re new to the magic formula. This will stop you from moving forward with potential errors in your pattern numbers.
There are two ways you can check your numbers using the row or round count as well as the stitch count, which I’ll explain below.
Checking the Rows/Rounds
The total number of rows or rounds that the shaping is worked over (b) should be the same as c multiplied by e plus f multiplied by d. If you look back, you’ll see that these letters match the ones used in shaping rate 1, followed by shaping rate 2.
To check my example, the shaping is worked over 70 rounds. 4 multiplied by 5 is 20, and 5 multiplied by 10 is 50. Adding them together, I get 70, which tells me that my numbers are correct.
It’s easier to work this out in a spreadsheet. Just use:
=b=(c*e)+(f*d)
Make sure to replace the letters with the appropriate cell references in your spreadsheet.
If the cell result says TRUE, you can be sure that your numbers are correct. If you get FALSE, you need to check your equations for errors.
Image description: A woman in a white ribbed sweater and jeans sits on a sofa knitting.
Checking the Stitches
The total number of stitches you want to increase or decrease at every shaping point (a) should be the same as e plus d. If you look back, you’ll see that these letters match the number of times an increase or decrease is worked in shaping rates 1 and 2.
To check my example, I would like to increase by 15 stitches at each shaping point. 5 plus 10 is 15, which tells me that my numbers are correct.
In the spreadsheet, you’d just write:
=a=e+d
Make sure to replace the letters with the appropriate cell references in your spreadsheet.
If the cell result says TRUE, you can be sure that your numbers are correct. If you get FALSE, you need to check your equations for errors.
Applying the Formulas to Other Sizes in Your Range
Once you have worked out the shaping rates for one size, as long as you are using cell references rather than typing out the numbers, you can drag the formulas across the other sizes using the fill handle.
Do this by highlighting the cells you want to copy the formulas over from, then click and drag on the blue square you see in the bottom right-hand corner of the highlighted cells. Pull it across as many sizes as you need before releasing it. You will automatically generate results for the remaining sizes.
Conclusion: Calculating Shaping Rates Using the Magic Formula
Discovering the magic formula was a game-changer for me as a knitting pattern designer and one that I use whenever I design a new knitting pattern.
Now, I am excited to pass it along to you so that you can stop wasting your precious time on manual calculations and finally automate your shaping rate calculations with ease.
How do you usually calculate your shaping rates? Do you have any tips or tricks that I haven’t mentioned here? Share them in the comments.
