Online Hat Size Calculator (US, UK, EU Sizes in Inches & CM)
Most people don’t know their exact hat size, and that’s usually where the fit problems start. A hat that looks great online often feels too tight or slides down because the size wasn’t right from the start.
This online hat size calculator helps you find your correct size in seconds. Just enter your head measurement in inches or centimeters, and it’ll show your hat size across US, UK, and EU charts. You can even download the results to save for next time.
If you haven’t measured your head yet, scroll down for a quick guide before using the tool.
Hat Size Calculator
Enter your head circumference in centimeters or inches to find your hat size (EU, US, UK).
Your Results
Head Circumference:
EU Size:
US Size:
UK Size:
Quick Guide: How to Measure Your Head for a Hat
If you don't already know your head measurement, here's a simple way to do it at home.
- Take a soft measuring tape. If you don't have one, use a string and measure it against a ruler.
- Wrap it around your head, just above your eyebrows and ears—where a hat naturally sits.
- Keep it snug but not tight, and note the number in inches or centimeters.
- Enter that number into the calculator above to find your true hat size.
For a detailed, step-by-step guide, check out our full guide on measuring your head for hat size.
Hat Size Conversion Chart
Here's a standard hat size chart you can rely on. It's based on the measurements most hat makers use, so it'll get you very close to the right fit. Please measure your head in inches or centimeters, then check where it falls on the chart below.
This chart shows standard hat sizes used by most brands. Use it with your head measurement to find your perfect fit across the US, UK, and EU sizing systems.
Quick Tip: Don't worry if your measurement doesn't match the chart exactly. Every brand makes hats a little differently and materials can stretch or shrink over time. If you are between sizes, pick the larger one. A slightly loose hat is easier to adjust than a tight one.
Now that you've got your hat size, it's easier to find the hat style that works best for you. Curious about all the options? Check out our guide on types of hats and their styles.
Final Thoughts
A hat only works when it feels right on your head. Your measurement gives you a starting point, but the real test is how it sits.
If it feels a little loose, a small pad or band can fix it. Remember that different brands and materials fit differently, so pay attention to the shape and comfort. When a hat fits well, it looks better, feels better, and you'll actually want to wear it.
Need help with your hat size? Use the calculator above or reach out to us. We can guide you to the perfect fit and make sure your next hat feels just right.
FAQs About Hat Sizes
What if my head size is 22 inches?
A 22-inch head usually fits a US size 7 or 56 cm in. Most hats in this size fit fine, but some brands may be a little tighter or looser, so it's always good to try it on if you can, or double-check the brand's sizing chart.
If my head is 22.5 inches, what is my hat size?
22.5 inches is between two sizes. We usually tell people to pick the bigger one. It will feel more comfortable, and if it's a little loose, you can use a small pad or adjust the sweatband to make it fit better.
What size hat is a 23-inch head?
A 23-inch head usually matches a US size 7 3/8 or 59 cm. You might want one size up if you like a bit more room.
What size is a 7-inch hat?
Hat sizes are based on head circumference, not the height of the hat. A US size 7 usually fits a 22-inch or 56 cm head.
Is 7 1/2 a big head?
Not at all. Size 7 1/2 is slightly above average, but it's still very normal. Most adults fall somewhere between 7 and 7 1/2. People often worry about "big head" sizes, but if you measure your head correctly, 7 1/2 should feel just right.
What's the average adult head size?
Most adult heads are between 22 and 23 inches, or 56 to 58 cm. That usually works out to US sizes 7 to 7 1/4.
Is it better to get a hat too big or too small?
Always go a little bigger if you're in between sizes. A slightly loose hat can be adjusted with padding or a sweatband. A tight hat can be uncomfortable and may leave marks.
How accurate are head size measurements?
If you measure carefully with a soft tape and keep it level around your head, your measurement is usually very accurate. Measure twice to be sure. Small differences matter, so taking the time to measure properly will save you from buying the wrong size.