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How to Design a Crochet Hat

by Laura Eccleston

10 Feb 2020


How to Design a Crochet Hat
As I take some time away from crochet, having been designing crochet patterns now for over ten years, it has given me some time to think about how it all began and what got me started in designing my own patterns and my own technique of putting them together.

When I first started to crochet, not including the yarny messes I used to make as a child, it was back in 2009 when I was pregnant with my daughter. I wanted to create some personal items for my child to be and knitting was not something that was satisfying enough. I was too slow, I hated the way how you could easily drop a stitch and for me that meant starting the whole process over again from the beginning. I was such a perfectionist in those early days. No over-sized grandma jumpers in this house I used to say, but of course that meant I pretty much didn’t create anything. That was until I saw Kirsty Allsopp on a Christmas creativity show in the UK. She was trying different crafts from around the country, one of which was crochet. I hadn’t thought about crochet in years. Back then it was not as popular compared to knitting and it was surprisingly hard to find patterns in my local stores, but I was like yes! One loop at a time, perfect, I can deal with that.

Sadly though, I quickly realised that the majority of patterns that were available were really old fashioned and frumpy. There was nothing contemporary on the market at all! Online was better, which is why I learnt the American terminology rather than the British way of writing things, because crochet seemed much more popular in the US. That said, I found what was available overly complicated and confusing. I got so frustrated in how designers were writing up their patterns. It was as if they were deliberately trying to make it hard so they could have this superior knowledge over me. I exaggerate of course and not all patterns were this bad, but it was enough to make me stop buying other people’s patterns and to start writing my own.

I never adapted patterns. It was much easier to start from scratch. I would think about the object I wanted to make, at that time a sun-hat for my daughter (that’s how long it took from Christmas) because I couldn’t find any in my local stores or online to buy as a finished item, and set about thinking how I could make one in crochet. Being mathematically minded helped, especially when I came across a formula for hats that seemed to work, which although wasn’t perfect, it enabled me to construct a size that would fit. It was like a eureka moment. The magic formula worked for all yarns, all hooks and still works today. 

The Magic Formula for Hats

Stitches in the round divided by the stiches in one inch.

When designing a hat the most important thing is sizing. Your yarn weight and hook size all affect a hat’s pattern. You can’t take an existing pattern and make it in a different yarn weight and expect the same size to come out, but what you can do is look at the yarn you have, the hooks you have and work a simple circular swatch in the round. Just make sure to use the same stitch you plan to use in your hat design. Starting with half double crochets or double crochets is a good idea for a beginner designer as the stitches will be clearer. 

When I design a hat I always make sure to work to a times table calculation, so for example let’s say I pick the 6 times table. My first round I start with 6 stitches, then the next round I have 12 and the next I have 18. You get the idea. Never work a random set of numbers as it will make a hat design so much harder for you and this formula won’t work at all.

Now you have your swatch, take your ruler and measure how many stitches you have in one inch. (I’m sorry to all those who work in centre metres, but it’s back to the old school days for you on this one). It may not be a perfect number, especially as you’re measuring in the round, you may have just over or just under, but make a rough calculation. For example, let’s say you have roughly 3 double crochets in one inch. Let’s write that down. 

The next thing to think about is who are you making the hat for? Is for a preemie baby or is it for a friend with an unusually large head? A quick guide…










9 – 12

14 – 16


18 – 20

20 - 22

21 - 23

22 - 24


23 – 30.5

35.5 – 40.5

40.5 - 46

46 – 51

51 - 56

53 - 58

56 - 61

Obviously it is much better if you can get an accurate measurement as all head sizes vary. This is only a guide, but it’s a useful place to start.

Let’s say I want to make a toddler hat, but I’m not sure the exact size so we need to take the average from the guide above, which is 17 inches. The stitches in your hat will always have a little stretch, plus the initial 4 chain loop or magic circle will allow for enough give so that the hat fits, but let’s take our magic formula above and see if our hat is big enough yet. Let’s count how many stitches you have in the round so far, in my fictitious swatch l have 18 so far as I’ve done three rounds in my 6 times table.

18 stitches in my round divided by 3 stitches in my inch = 6

No, it’s too small. We need 17 as our answer. So let’s work a couple more rounds and see if that’s enough. I work the next round and get 24 stiches in the round, then the next round where I finish with 30 stitches in the round. Let’s try our formula again.

30 divided by 3 = 10

Almost there. Let’s try another two rounds. 36 stitches at the end of my next round, then 42 stitches by the end of my next round. Let’s try our formula again.

42 divided by 3 = 14

So close! Let’s try one more round. We finish our next round on 48 stitches.

48 divided by 3 = 16

This is still just slightly too small. The hat would probably still fit as crochet is very forgiving, but it’s always better to see if another round would be a better fit. Sometimes working an extra round can make it way too big, but in this case you will see that it is very close to the final size we need as well, but just slightly bigger, which I feel is always better. Room to grow!

54 divided by 3 = 18.

So we can finally stop here if we want to, working our increase rounds in the six times table. Now we can have some fun. (Read further down on how to get exact measurements.)

Working the length

Whatever you crochet now won’t affect the sizing of the hat as long as you stick to 54 stitches in the round (in this example). You can keep things simple and keep working in double crochets, working only one stitch in every stitch around or you can crochet a pattern in a different stitch, but just make sure to stick to those 54 stitches in a round. Sometimes it’s worth thinking ahead. If you plan to crochet a fancy stitch on the length part, think about your times table. Does your fancy stitch work to your times table? Will it match 42, 48 or 54 stitches? If you’ve made a hat before this can sometimes be useful to jot down and remember for future reference.

When you’re finished you should find that your hat fits pretty well. If however it’s a little looser than you hoped for you can add a round or two of single crochets, which can bring in the edge. If it’s a little too snug then it may be worth going back to your increase rounds and adding an extra increase round. Sometimes however, an extra increase round can make the sizing just way too big, but the last round is too small, so what do you do then?

Adjusting the formula and getting it perfect

If you reached a round of 48 stitches, with a circumference of 16 and it was too small, but when you crocheted a round finishing on 54 stitches and it was way too big at 18 you can divide the times table formula in half. Instead of working an increase of every 6th stitch, which you have been doing (you should find all your increases match up in little Vs, if they don’t then you’re adding stitches either at the beginning or the end), you can work an increase round by adding increases on every 12th stitch instead. In this case you would end up with 51 stitches. 51 divided by 3 = 17. Now that’s a perfect fit!

Then simple continue with your length rounds.

You can also apply this method even further by dividing your formula into thirds or quarters, so instead of working an increase on every 6th or 12th stitch, you can work an increase on every 18th or 24th stitch. You can see this matches your 6 times table.

Sunhats, brims and making it fancy

Hopefully now you have a basic format for your hat design, but so far this has only explained a basic beanie design. What do you do if you want to add a brim or turn it into a sunhat. After you have finalised your beanie hat, to add a brim you will need to make more increases. I find the best method to quickly create volume and size is to double up your stitch count immediately. So let's say you have 54 stitches in the round still, we want to add an extra stitch in every stitch around so we end up with 108 stitches. This will create a lovely wide brim eventually. Each round after that go back to your 6 times table, so add an increase on every 6th stitch like before. Whatever your double up stitch count is, it will always fit your initial times table choice.

If you find this too big however and the edges are just way too wavy and floppy after a few rounds, you may prefer a more cloche design. To create this design instead of doubling up, skip the doubling up round and create a gentler increase by only working the 6 times table (or whatever table you're working to) like before, so on the next round from 54 stitches, instead of 108, you would have 60 stitches, then 66 on the next round, then 72 etc etc.

If both of these methods are wrong for you, say the double up technique is too floppy and wavy and the cloche technique is too, well, clochy and low, then you will need to work something in between. You will need to pick a times table that is less than the original one you chose. So instead of the 6 times table, perhaps work to the 4 times table, or the 3 times table. To do this increase on every third or fourth stitch instead and then follow that times table for every round after that. You may find that your stitch count won't divide exactly, you could end up with an extra stitch or two at the end, but to deal with this you could crochet the last few stitches together so that on the next round the stitch count will fit with your times table. If that's too messy for you as a fix, maybe find a times table that is less than 6 but fits your stitch count. So you could choose the 3 times table, 54 divided by 3 is equal to a whole number. Then your 3 times table will work on every round after that perfectly. Hopefully this gives you lots of ideas for adjusting sizes for brims. 

When you're happy with your brim you can add extra flourishes like a shell stitch or picot edging, maybe even a set of flowers to sit on the brim, whatever you desire!

I hope you have found this articles useful. You can watch a video tutorial here I made a few years ago, which looks at the maths involved in designing a hat on the times table method of increasing.

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