Ok, on to more shapes! This one is a rectangle, and you can tweak it to be as long as you want. **(Do you already know the dimensions of your desired rectangle? Scroll to the bottom to figure out the exact pattern you need!)**

Just like the square pattern, you work this one in rows (every row you chain one and turn), so that all of the outer edges are nice and straight.

In case you’re wondering, if you omit the ‘turns’ and crochet in the round (i.e. crochet the square or rectangle so that the same side of the stitch always faces you), the diagonal lines in the square/rectangle will curve. (I found this out the hard way.) It only becomes really noticeable past 10-12 rows, though. The reason is: whenever you are single crocheting in rounds, with the same stitch side always facing you, each stitch is slightly offset when compared to the stitch below. (If you’re right-handed, that means it will be offset a little to the right.) It amounts to about a 9 degree offset from perpendicular. (I know this because I went down that rabbit hole a while back.)

But I digress…

And … **MATH INTERLUDE** … cue guitar solo.

Just like the square pattern, I’m assuming every single crochet stitch is as tall as it is wide and that every stitch is identical in size to every other stitch.

Every rectangle represents a row (and I’ve included the first row of the stitch diagram to give you a sense of how this diagram fits in with the finished rectangle). I’m calling the height or width of each stitch *x*. Since you can start with as many chain stitches as you like (to make your rectangle longer) I’m calling the number of starting chain stitches, N, just like in the pattern.

For the first row (the inner rectangle), the top and bottom side length is 2*x*, while one of the side lengths is *x* + N*x* + *x*. So,

P_{1} = (2*x*) + (2*x* + N*x*) + (2*x*) + (2*x* + N*x*) = 8*x* + 2N*x*

So this first row will have a total of 8 stitches plus twice your original chain length of stitches.

For the second row, the top and bottom side length is now 4*x*, while one of the side lengths is now 2*x* + N*x* + 2*x*. So,

P_{2} = (4*x*) + (4*x* + N*x*) + (4*x*) + (4*x* + N*x*) = 16*x* + 2N*x*

So the total stitch count just increased by 8 stitches.

Next up:

P_{3} = (6*x*) + (6*x* + N*x*) + (6*x*) + (6*x* + N*x*) = 24*x* + 2N*x*

The number of stitches in this row increased again by 8.

The first few rows of your rectangle will look long and skinny, but as you add more and more rows, the ratio of the side lengths will become closer to one, so your rectangle will look ‘fatter’ the larger it gets.

**Do you already know the dimensions or aspect ratio of your rectangle?**

Then you can figure out your entire pattern before hand! The whole point of the following exercise is to determine how many chain stitches to start with. Once you do that, you follow the pattern for a given number of rows, then you’ve got your rectangle exactly how you want it!

Method #1: Let’s say you already know the dimensions of your desired rectangle and you just want to figure out how to use this pattern to make it.

You’re going to need to determine the size of one of your single crochet stitches first. Start by chaining 10 and making a couple rows of single crochet stitches back and forth using the exact same yarn, hook and tension as you’ll use when making your rectangle. Using a ruler, measure a certain number of stitches across (let’s say you measure 8 full stitches across). Take that measurement and divide it by the number of stitches you measured (8, in this example). That’s the size of one of your single crochet stitches! (We will still assume your stitches are as wide as they are tall.)

Now you’ll need to find what your desired length and width are in terms of single crochet stitches (not in cm or inches). Take the desired length of your finished rectangle (in cm or inches or whatever) and divide it by the size of one single crochet stitch (you have to use the same units by the way). Call this value *L*. This represents how many single crochet stitches will make up the longest side of your finished rectangle. Do the same thing with your desired width. Call this value *W*.

To find your starting chain length: subtract the number of Sc stitches that make up the final width (*W*) from the number of Sc stitches that make up the final length (*L*). (The number of starting chain stitches is referred to as N in the pattern.) So,

N = *L* – *W*

The number of rows you will need to make is just half of your width, *W*, measured in single crochet stitches. So, the number of rows you’ll need to make is just *W*/2.

Method #2: Let’s say you know the aspect ratio of your rectangle and how many rows you want to make.

Let’s call the total number of desired rows, *n*, and the aspect ratio of your length compared to your width, *l*:*w*. (For example, if your desired length-to-width ratio is 3:1, then *l* would be 3 and *w* would be 1.)

This calculation is a one-stepper. N represents the number of starting chain stitches.

If high school math was a distant memory, here is the step by step breakdown of this equation:

- Perform the subtraction inside the brackets. (Subtract
*w*from*l*.) - Take this number and divide it by
*w*. - Take that new number and multiply it by 2, then multiply it by
*n*.

As an example, if I wanted a 10 row rectangle (*n* = 10) with an aspect ratio of 3:1 (*l* = 3 and *w* =1), this is what my calculation would look like:

So, N = 40 chain stitches.

Have fun!

Thank you for posting this. I love that you took the time to explain the math behind the shape!

This is the pattern I need for my Pet Blankets that I make and donate to my local Pet Shelter however the math is a bit too much. I prefer a step by step tutorial ie…ch 10 +1 turning st. Make 1 sc in the next 10 sets, etc). Please consider doing this type of tutorial. Thank you

Can the Ideal Rectangle be used to make a rag rug?

Thanks

That’s the same thing I’m trying. 🥰

Wow amazing explanation. Maths is like Martian to me. And yet I was able to calculate the starting chain according to what length and width I wanted my rectangle to be. The only difference is I did it with double crochet.

Let’s hope it still works. I’ll update when I finish the project.

Thank you