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Sizing
Hat Size Calculator
Enter your head circumference to get your fitted hat size and S/M/L.
Fitted hat size
—
US fitted.
| Size (S/M/L) | — |
|---|---|
| Circumference (cm) | — |
| Circumference (in) | — |
| — |
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Enter your figures above to see the step-by-step working.
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How the Hat Size Calculator Works
A US fitted hat size is simply your head circumference in inches divided by π — because a hat is a circle and its size is the diameter. Wrap a tape measure around the widest part of your head, about an inch above the ears and eyebrows, to get the circumference, then the calculator gives the fitted size to the nearest eighth plus the S/M/L equivalent.
For example, a 22½-inch head is about a 7⅛ fitted, or Medium. Sizes run to the nearest eighth, so round to the closest available hat.
fitted size = head circumference (in) ÷ π
Frequently Asked Questions
How do I measure my head for a hat?
Wrap a soft tape around the widest part of your head, roughly an inch above your ears and eyebrows, and read the circumference in inches.
How is fitted hat size calculated?
Divide the head circumference in inches by π (about 3.1416) and round to the nearest eighth. A 22½-inch head is about a 7⅛.
What is my S/M/L hat size?
Small is about 6⅞–7, Medium 7⅛–7¼, Large 7⅜–7½, and X-Large 7⅝–7¾.
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