Knit & Crochet Hat Size Chart + How to Size a Hat the Right Way

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When it comes to making a hat, the fit needs to be just right. You need a reliable knitting and crochet hat size chart for standard sizes to start off with. Plus you need to know the actual hat measurements for these standard sizes. This guide is just what you need to properly size your hat so it fits perfectly (with or without a pattern!)

UPDATED: AUGUST 3, 2023 BY BRITTANY
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This guide includes a knitting and crochet hat size chart, and instructions to properly size a knit or crochet hat.

Making a hat that fits may not seem tough at first, but there’s more to it than just measuring the circumference and length.

This guide was designed to answer all your questions about sizing a hat and knitting or crocheting a hat that fits. We’ll look at things like how to measure a hat, and negative ease (and what that means for hat sizes), and then we’ll help you apply what you learn to a real-life project.

Here’s a quick overview of the topics we will cover in this article:


Knit and Crochet Hat Size Chart for Different Ages

For a hat to be snug (to keep your head and ears warm), it needs the right amount of stretch. But how much? And how long does it need to be? We’ll get to that in a minute.

But first, you have to know your starting point, and that’s where industry standards come in handy.

The following chart shows standard head circumference measurements for different age groups:

Knit and Crochet Hat Size Chart: Circumference

Different Age GroupsHat Circumference Range
(inches)
Preemie9-12
0-3 months (newborn)13-15
3-6 months15-16
6-12 months16-17
Toddler17-18
Child18-20
Teen20-22
Women’s21-23
Men’s22-24
For more reference, see the Craft Yarn Councils Head Circumference Chart

The Craft Yarn Council is my go-to resource for anything size-related, but one thing you won’t find in their standard head circumference chart is a list of recommended hat lengths.

But no worries, we have our own in-house hat length chart that has served us well for all of the hat patterns you’ll find on this website.

The following chart shows the total hat lengths for different age groups:

Standard Knit and Crochet Hat Size Chart: Lengths

Different Age GroupsTotal Hat Length
(inches
)
Preemie4
0-3 months (newborn)5
3-6 months5.5
6-12 months6.5
Toddler7
Child7.5
Teen8
Women’s8.5
Men’s9
Knit and Crochet Hat Size Chart for Hat Lengths

One thing to note about a pattern you might be following:

Anytime you follow a pattern from a book, magazine, online, or here on this website, you can trust that the fit will be right (as long as your gauge matches the pattern), and there are no additional steps you need to take. Just choose the size you need from the pattern notes and follow the instructions for that size.

That being said if you don’t have a pattern and you want to work something up on your own, you’ll need to follow everything in this guide to ensure a proper fit. It’s not for everybody, but it can be a lot of fun if you like this sort of thing.

Two Measurements for a Hat That Fits

Whether you’re following a pattern or making your own, it all starts with knowing how big your head is. Fortunately, sizing a hat is much more straightforward than a sweater for example.

To make a hat that fits, you only need two basic measurements:

  1. Head circumference
  2. Length

In either case, it’s safe to assume that these measurements will be suitable for any type of hat you plan to make (top-down, bottom-up, flat or slouchy).

Where do you measure your head for a knit or crochet hat?

To measure circumference: Wrap a tape measure around the middle of the forehead, making sure it’s straight all the way around (not twisted). You want it snug (but not too snug), and not sagging. Record the measurement with as much detail as possible; keeping it to one decimal place should be accurate enough.

To measure the length of the hat: position the tape measure in the middle of the crown and run it down one side to the bottom of the ear. Then record that number as the hat length.

If you’re following a pattern, you can go back to your pattern and choose the best available size to accommodate your measurements.

Most, if not all, professionally written crochet and knitting patterns will have ‘size groups’ instead of individual sizes. Just look for the circumference size ranges for each group (it should be included somewhere in the pattern). It’s perfectly safe to rely on the sizing of these size groups as long as you choose the size based on your measurements.

As long as your gauge matches what’s provided in the pattern, it’s safe to assume the hat will fit when it’s done. If this is the first time you’re hearing about “gauge”, read our Ultimate Gauge Guide before you start on your hat. Trust me… You’ll be glad you did.

How to Size a Hat If You Can’t Take Measurements

If you can’t take custom measurements, you can just as easily use standard measurements.

Although you can find hat size charts all over the internet, the most reliable measurements will come from The Craft Yarn Council’s website.

Take a look at their head circumference chart and find the age category for the hat you wish to make. In their chart, you’ll notice there isn’t a single measurement for each size. Instead, they include size ranges.

For example, the head circumference for a toddler is listed as 16-18″. This range is intended to include children between the ages of 1 and 3. Since their head sizes will vary based on the individual, and their specific age, a range is a safer bet to make a “one size fits all toddlers” kind of approach.

So this begs the question: what size in the range should you pick?

When we design a hat pattern for B.Hooked, we use the average of the range, and that has worked really well for us. This might seem like you could end up with a hat that won’t fit, but there’s one more thing to consider.

The finished circumference of the hat isn’t the same size as the circumference of your head.

If you make a hat that is the exact circumference you measure or the exact size of the recipient’s head, the hat will be too loose.

That leads us to our next topic.

Negative Ease

Any traditional “beanie” you buy in a store will stretch when you put it on. That is negative ease at work. If the hat didn’t stretch when you put it on it wouldn’t be very warm, and it may not even stay on. Negative ease is needed to cause the stretching which leads to the best fit.

Negative ease is a fixed measurement that is subtracted from the measured head circumference.

How much you ask? Fortunately, it’s pretty straightforward. A standard and widely accepted negative ease for crochet and knitting hats is 2.55″, which means you should subtract 2.55 inches from your head circumference. Why? Because most stitch patterns and yarn combos will allow the project to stretch at least this much.

To make things easier for you, here’s the exact knit and crochet hat size chart we use in the patterns here at B.Hooked. This chart was derived from the Craft Yarn Council head circumferences chart we talked about earlier. The “target circumference” represents the average circumference of the size ranges. Then we subtract negative ease to get the final number: the circumference the hat should actually be when it’s done.

Knit and Crochet Hat Size Chart: Actual Hat Measurements

Target Circumference
(inches)
Negative Ease
(inches)
Band Circumference
minus Negative Ease
(inches)
Preemie10.52.557.95
0-3 months142.5511.45
3-6 months15.52.5512.95
6-12 months16.52.5513.95
Toddler17.52.5514.95
Child192.5516.45
Teen212.5518.5
Women’s222.5519.45
Men’s232.5521.45
Knit and Crochet Hat Size Chart for B.Hooked Hat Patterns

How to Calculate Crown Diameter for Top-Down Hats

When you’re winging your own hat pattern and working it top-down like this hat here, you need to increase your starting circle to a certain point called the crown diameter. Then increases are no longer needed to work the body and band of the hat. Since the crown circumference generally sets the widest point of the hat, this calculation can be the difference between a hat that fits and one that doesn’t.

To calculate crown diameter (flat circle diameter): Divide your target hat circumference (with negative ease subtracted, not your actual circumference measurement) by 3.14 (pi).

The number you get is as wide as your crown can be. To put it more simply, this crown diameter is as wide as your circle can be before you stop increasing.

Looking at Hat Sections to Judge Hat Length

Breaking a hat into sections will help you plan for a hat that’s the right length. Flat and sewn hats are the exception to this but if you’re making a top-down or bottom-up hat, you can break the pattern into three main sections:

  1. crown
  2. body of the hat
  3. band (ribbing)

The hat length you measured or pulled from our chart is the total hat height of all three sections.

The crown and band will usually be a fixed length and the hat body varies based on the overall size of the hat. The crown height can be calculated with a simple equation:

To calculate the crown height, divide your target hat circumference by 6.28

When it comes to band height, we can trust a set of standard measurements. Here’s the knit and crochet hat size chart we use for band height.

Knit & Crochet Hat Size Chart for Band Height

Different Age GroupsBand Height
(inches)
Preemie1
0-3 months (newborn)1.3
3-6 months1.4
6-12 months1.6
Toddler1.8
Child1.9
Teen2
Women’s2.2
Men’s2.3
Standard Band Heights for Knit and Crochet Hats

It’s worth noting that any pattern you follow will do all of this for you, but if you like learning how a hat pattern comes together, this is it!

With the crown height calculated and the band length pulled from a standard set of sizes, this leaves the body to make up the rest of the total hat length.

How Long Should a Slouchy Hat Be?

Slouchy style hats, or hats that hang off the back of the head, have grown in popularity over the years. Fortunately, you only have to change one thing to make any hat a slouchy hat – the length.

As a general rule of thumb, add 2 inches to the sides of the hat to make it slouchy.

From the podcast…

Need to change the size of a hat pattern? This episode of the podcast will help you do just that.

Hit the play button below to listen!