Hat Size Calculator

Quick answer: measure round your head where the hat sits and find it on the chart: 22 in is a US 7, 22¾–22⅞ in (58 cm) is a US 7¼, 23⅝ in (60 cm) is a US 7½. A UK size is one eighth smaller than the US size for the same head, and an EU size is simply your head in centimetres. Between two sizes, go up — every hatter below says so.

How to use it

Wrap a soft tape round your head where a hat sits — across the middle of your forehead and just above your ears, round the widest part at the back — snug but not tight, and type the number. Fractions work: 22 3/4. No tape? Use a piece of string and measure the string flat, or press Print a paper one for a tape you can cut out (print it at 100%, then check 10 cm with a ruler). Already know a size? Choose A hat size and convert it between US, UK and EU.

Why four charts instead of one

Hatters do not share one table. Lock & Co. makes a US 7¼ for a 22⅞ in head; New Era and Tenth Street Hats make theirs for 22¾ in. Letter sizes are worse: at Stetson “Medium” covers 6¾ to 7⅛, at Tenth Street “M” is a 7, and New Era’s stretch-fit S/M runs all the way to 23½ in. So the calculator reads your head on each chart and shows each one’s own answer. Stetson’s chart even disagrees with itself — its inch column puts a 22¾ in head in Medium, while its size column calls a 7¼ hat Large — and the tool says so when it happens.

US, UK and EU hat sizes

Lock & Co.’s chart, the only one here with all three systems side by side. The one chart here with all three systems side by side. EU sizes are the head in centimetres; UK sizes run one eighth smaller than US for the same head.

Fitted cap sizes

New Era’s 59FIFTY chart. Its stretch-fit caps come in ranges that overlap: S/M 22⅜–23½ in, M/L 23⅛–24¼ in, L/XL 23⅞–24⅝ in — a 23¼ in head is inside two of them.

Cowboy hat sizes

Stetson prints letter sizes as ranges, with gaps between them. A head in a gap gets the next letter up — Stetson’s own rule.

Between two sizes

Every hatter here says the same thing: between two sizes, go up. “If your measurement falls between sizes, order a size up.” (Stetson) “If you’re between sizes, we recommend rounding up.” (New Era) “If the measurement is in between sizes on the hat size chart, choose the next larger size.” (Tenth Street Hats) “If your measurement falls between two different sizes, we recommend sizing up to the nearest 1/8-inch. You can then use the hat’s sizing tape to size your hat down if necessary.” (Hats Unlimited)

A hat that is a touch big can be taken in; one that is small cannot be stretched much. Women’s hats sold as one size usually fit “a head circumference of around 21 1/2 to 22 1/4 inches” (Hats Unlimited), so measure before you trust one-size.

Why a US hat size looks so small: it is roughly your head’s width, not its circumference. Divide the circumference in inches by π (3.14) and you land within an eighth of a size of every row on the Lock & Co., New Era and Tenth Street charts — our own arithmetic, checked row by row, not a rule any hatter prints. Stetson’s letter ranges pair their ends more loosely (its Medium tops out at 7⅛ and 23 in, where the others put 7⅛ at 22⅜–22½ in), which is one more reason to read each chart for itself.

Three worked examples

A 22¾ in head. US 7¼, UK 7⅛, EU 58 on Lock & Co.’s chart — and a 7¼ fitted cap at New Era, whose 7¼ is made for exactly 22¾ in. At Stetson it is a Medium by the inches and a Large by the size; try both.

A 58 cm head. That is 22.8 in, just under Lock’s 22⅞ for a 7¼ and just over New Era’s 22¾. So it is a 7¼ at Lock and, sizing up, a 7⅜ at New Era and Tenth Street. One head, two US sizes, a size apart — exactly why the tool shows each chart.

“I wear a UK 7.” On Lock’s chart a UK 7 is a US 7⅛ and an EU 57, made for a 22½ in head.

Common mistakes

• Measuring too low or too high. The tape goes where the hat sits: mid-forehead and just above the ears — not across the eyebrows, not round the crown.
• Pulling the tape tight. Snug, not tight. A tight measurement buys a hat that gives you a headache by lunch.
• Reading a UK size as a US one. The UK number is an eighth smaller for the same hat; a UK 7⅛ and a US 7¼ are one size.
• Trusting a letter size across brands. “M” is a 7 at one hatter and 6¾–7⅛ at another.
• Rounding down when between sizes. Every hatter here says go up.

More on Needle Style

Once it fits: cowgirl style outfits, cowgirl hairstyles that work under a hat, rodeo outfits, what to wear for a day at the races and Cowboy Carter outfit ideas.

Charts read on the day checked: Lock & Co. Hatters, Tenth Street Hats and Hats Unlimited (2026-09-20); New Era and Stetson (2026-09-22).

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