Hat Size Calculator
One tape-measure reading, about 30 seconds. No camera, no photo, no sign-up.
Enter the number you get when a soft tape measure goes around your head — the same number a hat seller would take. The tool places it in the band most adult hats are built around, so you know whether a standard size, a smaller one or an extra-large is the better starting point.
It is a starting point, not a verdict: fit also depends on the shape of the crown, your hairstyle and how snug you like a hat to sit.
Your head circumference
Around your head, just above the ears and across the middle of the forehead — the number a hat seller would take.
Enter your number to see where it falls in the common adult range.
Calculated in your browser — the number you type is never sent to a server.
What the common band means
Off-the-shelf adult hats are built around a fairly narrow range of head circumferences — roughly 54–62 cm (21.3–24.4 in). Below it, youth sizing or an adjustable strap is the closer match; above it, look at XL styles or adjustable closures. If your number sits right on an edge, measure once more before choosing.
Three lines, and you have your number
Run the tape around your head, just above the ears and across the middle of the forehead — that ring is what hat sizes are based on.
Keep the tape level and snug, the way a hat band would sit — not tight.
Read the number where the tape meets itself, and enter it above.