DIY brain hat!

I have been inspired by the rush of brain hats on the internet of late. And you too can make a brain hat! It’s an easy project – you only need to know how to knit, purl, and decrease – but long. (You have to make approximately a bazillion brain ridges.)

I adapted my pattern from this one, to both make it cooler and also more anatomically correct. (Anatomical errors, including a couple of really glaring asymmetries, are solely due to insufficient knitting skill!)

To do this pattern, you’ll need to know how to knit (K), purl (P), knit 2 together (K2tog), purl 2 together (P2tog), and cast on (that’s my preferred method, there are many) and off (again, one of many methods).

1. The Hat

So the secret here is that you could theoretically use any old beanie – you don’t have to make it yourself. As long as it’s snug to your head, that’s all that counts.

But if you want to make your own, you will need:

  • Worsted weight yarn (100g/220yd) – I used Cascade Yarns’ #220 Peruvian Wool in color 8010 (natural/off-white), because it’s the white matter of my brain (I’m so clever)
  • Size 8 double pointed needles
  • Size 8 round needle (16in) – optional, if you choose to do the whole thing with double points, though if you use a round needle you’ll still need double points for the decrease
  • Tapestry needle (to sew in the ends)

Cast on 96 stitches onto the round needle (or double points) using whatever method you prefer. (With this weight yarn and size needle, that should come out to about 20 inches around.) If you need to size the hat up or down, do so in multiples of 8. Then cast on one extra stitch, slide it across to the other side of the round needle, and knit that stitch together with the very first one you cast on. So now you’ll have 96 stitches again, and your hat is round.

K4, P4 (knit 4, purl 4) until your hat is about 5.5-6 inches tall. You want to be pretty close to the final height of your hat at this point, because we’re going to finish it in 8 more rows.

Then we’ll decrease:

  • Row 1: K2, K2tog, P4
  • Row 2: K3, P2, P2tog
  • Row 3: K1, K2tog, P3
  • Around this point you’ll probably have to switch to the double points, if you were using a round needle.
  • Row 4: K2, P1, P2tog
  • Row 5: K2tog, P2
  • Row 6: K1, P2tog
  • Row 7: K2tog
  • Row 8: K2tog

Finish it off and sew in the ends. You now have your hat! Hopefully it fits, or you risk the judgment of generations of phrenologists. (Not that you should feel bad about being judged by phrenologists, because they are hilariously wrong and also extinct.)

2. The Brainy Bits

You will need:

  • Worsted weight yarn (100g/220yd) – I used the same yarn in color 8408 (smoke)
  • Your double points from up above
  • Your tapestry needle from up above

Now you are going to knit a million I-cords, in which you knit across your row, slide it to the other end of the double point, and start again, until your face turns blue. My I-cords were mostly 5 stitches across, and a few were 6 stitches across. The shortest were about 6 inches long, and the longest about 18 inches. You can make them in whatever sizes you like, but the important thing is to make pairs. The brain is quite symmetric, so you want the two sides to have the same pattern. (I messed this up a couple of times, so my hat has a couple of cords that are less than an inch long to try to reclaim as much asymmetry as possible.)

Here’s an I cord before I turned it into brain:


An easy way to line things up is to sew a quick and crappy line down the center of the hat – follow a knit/purl border to keep it straight – and make things mirror across that.

I used a basic line drawing of a brain as inspiration, but I quickly discovered that I wasn’t going to get this to be as anatomically correct as I’d hoped, as the brain isn’t really strips – it’s folds. I wasn’t quite able to replicate the folding with strips instead.


I also made a pair of cerebellums to stick at the back of my brain. These were 18 stitches across, and traditionally garter stitched (not an I cord) for 6 rows, and then I decreased it by 4 stitches per row for 3 rows to round off the top. That’s:

  • Cast on 18
  • K across 6 rows
  • *K1 K2tog K1 K2tog* k until 6 from end then *K2tog K1 K2tog K1* (if you’re feeling fancy, ssk to be symmetric)
  • Cast off

So the cast off goes from 18, to 14, to 12, to 8. The last row there’s no knitting between the decrease blocks! Make 2 of these and attach them at the bottom at the back.

As you finish I-cords, and your cerebellum, just sew them down to the hat. Remember that your hat stretches – so don’t accidentally make it so your hat won’t fit by sewing down the cords to an unstretched hat! I attached pairs of I-cords at the same time as I finished them, so I could see what space I had left to fill and what shapes to make.

Here I’m about to add the very last I-cord – so you can see that I’m filling in around other cords.


Just keep making I-cords until you can’t see straight or your hat is full of brain! It’ll look something like this:

And with this, you’ll be the coolest kid on the block, assuming your block is full of neuroscientists.


2 thoughts on “DIY brain hat!

    1. I’m glad you like the pattern! You should be able to re-size it easily for any kid’s head just by changing the number and size of the strips you make, and of course picking a hat that fits her. A kid’s brain looks from the outside much the same as an adult’s, so if you’re going for anatomical correctness like I tried to it would just be a smaller version of what I made!


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