How to use this hat size chart and calculator
This hat size chart does the conversion for you. Wrap a soft tape measure around your head, about 1 cm above your ears and across the middle of your forehead, and type the number into the calculator in centimetres or inches. You instantly get your US fitted size, your UK size, your European size and your letter size, together with the size you would pick from New Era, Flexfit, Nike, Stetson and The Game.
The matching row in the chart below lights up, so you can see the sizes either side of yours. If you land between two sizes, the calculator says so and shows the next size up. Choosing a child’s age instead of typing a number gives a typical head size for that age, which is useful when you are buying a gift and cannot measure. Nothing you type leaves your browser, and the tool works the same on a phone as on a desktop.
International hat size conversion chart
Hat sizes come in four flavours: centimetres (used in Europe and by most brands as the underlying measurement), inches, US fitted sizes such as 7 ⅜, and letter sizes such as M or L. The chart below lines them all up so you can move between them without any maths.
| cm | Inches | US | UK | Letter |
|---|---|---|---|---|
| 46 | 18 ⅛ | 5 ¾ | 5 ⅝ | – |
| 47 | 18 ½ | 5 ⅞ | 5 ¾ | – |
| 48 | 18 ⅞ | 6 | 5 ⅞ | – |
| 49 | 19 ¼ | 6 ⅛ | 6 | – |
| 50 | 19 ⅝ | 6 ¼ | 6 ⅛ | – |
| 51 | 20 ⅛ | 6 ⅜ | 6 ¼ | – |
| 52 | 20 ½ | 6 ½ | 6 ⅜ | XS |
| 53 | 20 ⅞ | 6 ⅝ | 6 ½ | XS |
| 54 | 21 ¼ | 6 ¾ | 6 ⅝ | S |
| 55 | 21 ⅝ | 6 ⅞ | 6 ¾ | S |
| 56 | 22 | 7 | 6 ⅞ | M |
| 57 | 22 ½ | 7 ⅛ | 7 | M |
| 58 | 22 ⅞ | 7 ¼ | 7 ⅛ | L |
| 59 | 23 ¼ | 7 ⅜ | 7 ¼ | L |
| 60 | 23 ⅝ | 7 ½ | 7 ⅜ | XL |
| 61 | 24 | 7 ⅝ | 7 ½ | XL |
| 62 | 24 ⅜ | 7 ¾ | 7 ⅝ | XXL |
| 63 | 24 ¾ | 7 ⅞ | 7 ¾ | XXL |
| 64 | 25 ¼ | 8 | 7 ⅞ | 3XL |
| 65 | 25 ⅝ | 8 ⅛ | 8 | 3XL |
| 66 | 26 | 8 ¼ | 8 ⅛ | 3XL |
How hat sizes work
A US fitted size is simply the diameter of your head in inches. Take your head circumference in inches and divide by pi (3.14). A 23-inch head is 23 ÷ 3.14 = 7.32, which rounds to 7 ⅜. UK sizes run one-eighth smaller than US, so a US 7 ⅜ is a UK 7 ¼. European and French sizes are your circumference in centimetres, so a 58 cm head is an EU 58.
Letter sizes are the least precise. One brand’s S/M may cover 54 to 58 cm while another brand’s Medium stops at 57 cm. When a hat is sold in letter sizes, check the brand’s own range. Our calculator lists the most common brands so you can compare them in one place.
Hat size chart by hat type
The same head measurement works for every kind of hat, but each style is sold in its own way. A fitted hat size chart uses eighths of an inch, from 6 ⅞ up to 8 for most adults, because fitted caps have no strap and the size has to be right. When you use a hat size chart, fitted caps are the strictest case, so our fitted page lists every fraction with its centimetre and inch equivalent. Baseball caps come fitted, stretch-fit or adjustable, so the baseball hat size chart shows all three side by side.
The cowboy hat size chart follows the traditional hatter’s fractions from 6 ⅜ to 8, and many western hats also carry letter sizes from X-Small to XXL. Felt hats do not stretch, so when you are between sizes, go up. If you make your own hats, the crochet hat size chart and the knit hat size chart give head circumference, finished hat circumference, hat height and crown size for every age from preemie to adult. The finished hat is made smaller than the head, about 10% for crochet and 15% for ribbed knitting, so it stays on without being tight.
Hat size charts for the big brands
Brands publish their own charts, and they do not always agree with each other. The New Era hat size chart covers the 59FIFTY fitted cap, which runs from 6 ⅞ to 8 on the standard chart and up to 8 ¼ in some styles, plus the 39THIRTY stretch fit and the 9FIFTY snapback. If you are searching for a hat size chart New Era publishes for its fitted caps, the New Era fitted hat size chart gives each size’s exact centimetre value, because New Era prints them slightly differently from the pure formula.
The Flexfit hat size chart (often searched as a flex fit hat size chart) covers the 6277 stretch cap in S/M, L/XL and XXL, plus youth sizes. The Nike hat size chart covers adjustable caps in S/M, M/L and L/XL and the Swoosh Flex. The Stetson hat size chart lists fitted fractions alongside Stetson’s letter sizes, where Medium is 7 to 7 ⅛ and Large is 7 ¼ to 7 ⅜. The Game hat size chart covers its flex caps in S/M and L/XL. Our calculator shows all of these brands for your measurement at once, so you can compare before you buy.
Men’s, women’s and youth hat sizes
Most adult men measure between 55 and 60.5 cm. The men’s hat size chart starts at 6 ¾ and runs to 8 ¼ for big heads, with 7 ¼ as the average and 7 ⅛ to 7 ⅜ as the most common sizes. If you have been searching for a mens hat size chart for large sizes, look for fitted sizes above 7 ⅝ or XL and XXL stretch caps.
Children need their own charts. The youth hat size chart covers roughly ages 6 to 12, where New Era youth fitted caps run from 6 to 6 ¾ and many older children already fit an adult 6 ⅞. For babies and toddlers, the kids and baby charts list head size by age, based on WHO growth data.
Hat size chart in inches and US sizes
Many American shops measure heads in inches, and most online tape measures show both units. The hat size chart inches page converts every inch measurement from 20 to 25 inches into a fitted size, and the US hat size chart lists American sizes with their UK, European and centimetre equivalents. Remember that a US size is one-eighth larger than the same UK number, so always check which system a shop is using before you order.
Average hat sizes
The average adult man measures about 57.5 cm (22 ⅝ in), a US 7 ¼, and most men wear 7 ⅛ to 7 ⅜. The average adult woman measures about 56 cm (22 in), a 7. Only about one in five adults falls outside the 7 to 7 ⅝ range, which is why most fitted caps stop at those sizes and why extended sizes cost more.
Fit tips
- Between two sizes? Choose the larger one for fitted caps and felt hats. Wool and cotton shrink a little, and a too-tight hat leaves a mark.
- Choose the smaller size for stretch-fit and knit hats, which loosen with wear.
- Thick hair or a hairstyle that sits under the hat can add half a size. Measure the way you will wear it.
- A hat that is slightly big can be fixed with foam sizing tape inside the sweatband. A hat that is too small cannot be fixed.