How To Design Your Own Hat (Part 1: The Basics)


One of the main reasons I started designing my own hats was because I struggled to find crochet patterns that didn’t look like those crocheted Barbie toilet paper covers my grandmother had.

When I first started, it was complete guess work.  I didn’t know about even increases or flat circles and crocheted everything in a UK Treble/US Double crochet. Patterns evaded me (and still do to some extent).  I would always lose count of stitches and never knew where the designer intended for me to put my hook. My hats looked more like something out of the hyperbolic reef project, rather than a garment.

About 3 years and countless hats later, I feel relatively confident in my ability to make a hat to fit a head. But even now, I remain baffled by the lack of readily available information on how to design your own. These type of instructions are much more prevelant in the knitting community, Elizabeth Zimmerman being the classic example. It was reading her Knitters Almanac that really taught me how to design.

To save others the frustration I have gone through I thought it would be useful to lay out my process for designing a very basic beanie style hat.

To keep things simple, I am laying out the posts over a couple of days.  Today, I will just give an overview of the general principles and then tomorrow, we will look a the nuts and bolts of hat design.

Beanies are generally the easiest of hats as it follows a very simple pattern:

increases are worked over a flat circle to the desired diameter and then,

- the increases stop and the hat height is built up using rounds of the same number of stitches as the last increased row, or “worked even”.


Have I lost you? Let me explain.

Remember geometry class and those endless problems involving pi?  Well, contrary to what I told my math teacher about geometry being useless in ‘real life’, it actually comes in handy when making a hat.

Very often, you will know (at least roughly) the circumference of your recipients head.  Even if you haven’t measured, there are a variety of guides that give you the basic size range for head sizes. Hat sizes are about 1-2 inches smaller than the head size and have heights that correspond to circumference. No matter where you look, they are pretty standard.  My hats are generally sized as follows:


Age Head Size Hat Size Hat Height Flat Circle Diameter
0-6 months 13 – 15in 12 -14  inches 4.5 – 5 inches 4 inches
6-12 months 16 – 19 inches 14 – 18 inches 5.5 inches 4.5 inches
1 – 3 Years 18 – 21 inches 17 – 20 inches 6.5 inches 5.5 inches
4+ years 20 – 22 inches 19 – 21 inches 7.5 inches 6 inches
Women 22 inches 20 inches 8.5 inches 6.5 inches
Men 23 inches 21 inches 9.5 inches 6.75 inches


The range of measurements in sizes is usually covered by making a hat to the smallest size in an age range, quite simply because hats stretch, some more than others. Materials like wool are stretchier than cotton and certain stitches stretch more as well.  I like UK Half Treble/US Half Double Crochet for most hats as it is a good balance between creating a nice solid material, with a nice stretch in it.  Longer stitches, such as UK Treble/US Double, and shell stitch have a lot of stretch.  UK Double/US Single crochet is pretty tight, but does create a lovely, even fabric.

But really, the type of stitch you use is largely irrelevant. You need to use that stitch to increase steadily in a flat circle, until its diameter will give you a hat of the correct circumference. How do you know? Well, its that good ol’ geometric equation where

Diameter (the distance across the circle) = Circumference (the distance around the circle)/pi

You’ll see in the table above that I have calculated the diameters of the flat circles for most hat sizes. However, if you know the head size you are making for, you need to:

- Subtract 1.5 inches from the head circumference to get the hat size

- Divide the hat size by 3.14

The resulting figure is the diameter. Once you get your flat circle measuring something akin to the correct diameter, stop increasing and just crochet in the round until your hat is the right height. You can always use a balloon blown up to the right head size to check your sizing if the recipient isn’t readily willing and/or available (also balloons are great for blocking beanies.) 

So the next question is “How do I know how many rounds and how many stitches to work to for my increases?” That, my friends, is a question for another day. 

***Part 2 is available here***

The full interactive workbook is available here.

23 responses

  • Oo, thanks! I haven’t got the first clue about crochet but have dropped large hints that I’d like some beginner’s crochet things for Xmas, so hopefully in several decades time I might actually be able to make something!

  • Holy cow! While I design and make my own hats all the time (both knit and crochet), I always totally wing it using trial and error, intuition and prior knowledge to work out my sizing. I am so hopeless with maths, even reading that my brain was having major fits. I really want to sit down and try and work out what you are so thoughtfully telling us. Thank you.

  • Oh, there is nothing wrong with winging it. For hats for my kids, I can usually just eyeball it. The problem for me was that I had hat “orders” to custom make and that, combined with a desire to write up patterns for publication has forced me to really think about sizing and different yarns and gauge. I also think that crochet patterns are very prescriptive, with very little information out there about resizing, etc.
    And your eye is great, so I wouldn’t worry too much about changing what you do.

  • Ooh that is handy to know… lol yup I’m a winger too hehehe.
    I think probably the reason there isn’t much info on how to design crochet items is of the tradition within crochet that (perhaps even a bit of snobbery), crochet is sucha versatile and easy to manipulate yarn craft, a pattern is not really necessary, and if you know how to decrease and increase then you’re sorted pretty much.
    Of course it’s not really that simple ;-)

  • Thank you so much, Kat! This is the best! My friends are loving my first creation of it. I don’t know how to post a picture here, but contact me via email so I can send you one. I’m very happy with it. You are fabulous at clearly writing patterns. I can’t thank you enough for this gift!

  • that is sooooo wonderful.  I felt like such a muppet posting it, because it got some criticism on ravelry.  but if it helped even one person then in was so worth it.  I'd love a pic.  email is fine: or if you are a facebooker, you can tag it for Slugs On Th Refrigerator either way, I'd love to see it.

  • Can I just say – I LOVE YOU! Never has this been explained to me in such a simple, COMPLETE way!!! Thank you Thank you :)

  • Hi Kat, I was hoping I could connect with you to see about reposting some of this information on my blog, with credit and a link to you of course. When you get a moment, I would love to discuss. I can be reached at Thanks!

  • Hi, thank you so much for your post. However, I’m a little confused. When I divided 21 by 3.14 I got 6.68. How did you get 7.25? I’m just wondering because I’m trying to make a hat for my husband. He has a 24 inch head, so according to your post I should subtract 1.5, which is 22.5, then divide by 3.14, which is 7.17. Can you help? Thanks!!

  • Hi and Thank You! I just found your blog and LOVE the way you explained everything. I can follow most patterns but have always had issues when i tried to adjust things away from the pattern. These post spelled everything out for me. I Understand Now!!! Oh my goodness Thank you so much. Looking forward to reading more from you.
    Happily Following,
    Ashley @ Thereisnoplacelikehomemade

  • I realize I came across this a year after you posted it, but I wanted to tell you the timing is perfect for me!
    Thank you so much for laying this stuff out so simply. I have an almost impossible time reading patterns, so have never gotten into much knitting or crocheting. However, I love doing it. I normally just ‘wing it’ when crocheting since it’s easy to see/feel the shape as it happens… then just adjust accordingly. However, somehow I have turned into a grandmother! (EEEK!) I have a granddaughter to create stuff for. I’m needing to bone up on some skills.
    Thus, the perfect timing of coming across this tutorial you were kind enough to create. Thanks!

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  • Thanks sooo much for this article. Gives me so much more confidence in crocheting hats, and knowing that they will fit the intended wearer. I will be asking my husband to print off the chart for me!! :)