Hat Size Calculator

Created by Łucja Zaborowska, MD, PhD candidate
Reviewed by Bogna Szyk and Jack Bowater
Last updated: Apr 06, 2022

What size hat am I? If this question has been wondering around your head for some time now, our hat size calculator may offer you the perfect answer. 🎩

Computing children's, women's, and men's hat sizes with our calculator will take you less time than it did to read this sentence - it's just that simple!

Follow the article below to discover hat size conversion charts and your hat sizes in inches - using both the American & British versions. 👒

How to calculate your hat size?

In order to discover your hat size, you need to take measurement the circumference of your head and use one of the hat size charts. Be careful! American sizes are usually greater than British ones.

  • Range of international sizes: XS-S-M-L-XL-XXL-XXXL;
  • Range of American sizes: 6 1/2 - 8 1/8; and
  • Range of British sizes: 6 3/8 - 7 7/8.

🧢 International sizes for children are based on their age.

This may have left you wondering - hat size vs. circumference - how are they related? Move on to the next section of the text to find out!

How to measure head for hat?

Hat sizes are based on head circumference. To measure it correctly, you need to find the part that protrudes the most at the back of your head and connect it to the most protruding part of your forehead with a line that goes approximately 0.4-0.8 in (1 - 2 cm) above your ears.

💡 7 3/4 hat size doesn't equal the 7 3/4 inch head circumference.

Looking for the tiniest of hats? 👶
Go ahead and check your baby's head circumference percentile.

How to use the hat size calculator?

Wondering what's the 24-inch hat size? Search no more!

Enter you head circumference into our hat size calculator and obtain your results immediately - you may choose from 6 different length units, including both metric and imperial system.

Have you already found your hat size? How about checking out our other clothing tools:

Shoe size 👞 | Jacket size 🧥| Jeans size 👖

Circle shirt 👗 | Bra size 👙 | Ring size 💍
Tablecloth size 🍽️

Hat size charts in inches and centimeters

While international size charts tend to be rather straightforward, hat sizes still might be confusing - especially when it comes to American and British measurements. Both UK and US hat sizes use inches in different standards.

Using the charts below, you can find answers to the following questions, and many, many more:

  • What hat size is a large/ medium/ small? 🎓
  • What hat size is 24 in? ⛑️
  • What is hat size large in inches? 👑

Adults hat size chart
Head circumferenceInternational sizeUS sizeUK size
20.5 in/ 52 cmXS6 1/26 3/8
20.9 in/ 53 cmXS6 5/86 1/2
21.3 in/ 54 cmS6 3/46 5/8
21.7 in/ 55 cmS6 7/86 3/4
22 in/ 56 cmM76 7/8
22.4 in/ 57 cmM7 1/87
22.8 in/ 58 cmL7 1/47 1/8
23.2 in/ 59 cmL7 3/87 1/4
23.6 in/ 60 cmXL7 1/27 3/8
24 in/ 61 cmXL7 5/87 1/2
24.4 in/ 62 cmXXL7 3/47 5/8
24.8 in/ 63 cmXXL87 3/4
25.2 in/ 64 cmXXXL8 1/87 7/8

Children hat size chart

Head circumferenceAgeUS sizeUK size
15.7 in/ 40 cm0-6 months54 7/8
16.5 in/ 42 cm0-6 months5 1/45 1/8
17.3 in/ 44 cm6-12 months5 1/25 3/8
18.1 in/ 46 cm6-12 months5 3/45 5/8
18.9 in/ 48 cm12-24 months65 7/8
19.7 in/ 50 cm24-48 months6 1/46 1/8
20.5 in/ 52 cm4-8 years6 1/26 3/8
21.3 in/ 54 cm4-8 years6 3/46 5/8
Łucja Zaborowska, MD, PhD candidate
My hat is meant for
an adult
Head circumference
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