Headwear Sizing Guide

Hat Size Converter

Convert between US, UK, EU, and generic hat sizes using your head circumference. Our chart covers fitted sizes from 6 3/8 to 8 with measurements in both centimeters and inches.

Quick Converter

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Head (cm)	Head (inches)	US Size	UK Size	EU Size	Generic
51	20⅛	6⅜	6⅜	51	XS
52	20½	6½	6½	52	XS
53	20⅞	6⅝	6⅝	53	S
54	21¼	6¾	6¾	54	S
55	21⅝	6⅞	6⅞	55	S/M
56	22	7	6⅞	56	M
57	22⅜	7⅛	7	57	M
58	22¾	7¼	7⅛	58	M/L
59	23¼	7⅜	7¼	59	L
60	23⅝	7½	7⅜	60	L
61	24	7⅝	7½	61	XL
62	24⅜	7¾	7⅝	62	XL
63	24¾	7⅞	7¾	63	XXL
64	25⅛	8	7⅞	64	XXL

Click any row to highlight it. Sizes are approximate and may vary by brand.

Hat Sizing by Style

Different hat types fit differently even at the same labeled size. Knowing how each style sits on the head helps you pick the right size the first time.

Fitted Baseball Caps

These require your exact size. They sit on the mid-forehead and wrap around the full circumference. No adjustment is available, so precise measurement is essential. New Era 59FIFTY is the most common fitted cap standard.

Fedoras & Dress Hats

Fedoras typically sit slightly above the ears. They should feel secure without pressing into the forehead. Many fedoras use the US fractional sizing system. Quality felt hats can be steamed and shaped for a custom fit by a hatter.

Beanies & Knit Caps

Beanies are the most forgiving style due to their stretch. Generic S/M/L sizing usually works well. If you prefer a slouchy fit, size up. For a snug skull-cap fit, match your exact circumference or go one size down.

Bucket Hats & Sun Hats

These typically use S/M/L/XL sizing and sit lower on the head than caps. They should cover the tops of your ears without sliding down over your eyes. Wide-brim sun hats often run slightly large to account for a relaxed fit.

How to Measure Your Head for a Hat

Position the Tape

Place a flexible measuring tape (or a string you can measure afterward) around your head about one inch above your eyebrows and ears. This is where most hats sit. Keep the tape level all the way around the back of your head at the widest point.

Take the Reading

Pull the tape snug but not tight. You should be able to fit one finger between the tape and your forehead. Record the measurement in both centimeters and inches. If using a string, mark the overlap point and measure it flat against a ruler.

Choose Your Size

Match your circumference to the chart above. If you fall between two sizes, round up for a comfortable fit. Hats made from natural fibers like wool or cotton may shrink slightly over time, so the next size up is a safe choice.

Keep in mind: Head shape matters as much as circumference. Two people with the same measurement may need different hat shapes. Oval heads suit most Western hat styles, while rounder heads often fit better in bucket hats, beanies, or adjustable-back caps.

Frequently Asked Questions

What is the average hat size for adults?

The average adult hat size is US 7 1/8 to 7 1/4 (57-58 cm circumference), which corresponds to a medium in generic sizing. Women's heads tend to average slightly smaller at US 7 to 7 1/8 (56-57 cm), while men average US 7 1/8 to 7 3/8 (57-59 cm). These are general averages and individual variation is significant.

Are US and UK hat sizes the same?

They are very close but not identical. US and UK hat sizes both use a fractional numbering system, but UK sizes run about 1/8 size smaller for the same head circumference. For example, a 58 cm head is a US 7 1/4 but a UK 7 1/8. The difference is subtle enough that many brands treat them as interchangeable.

What is the difference between fitted and adjustable hats?

Fitted hats are manufactured to a specific head circumference and do not have adjustment mechanisms. They provide the most precise and streamlined fit. Adjustable hats use snapbacks, strapbacks, or elastic bands to accommodate a range of head sizes, typically covering small-to-medium or medium-to-large ranges. Choose fitted for the best look and adjustable for versatility.

Will a hat stretch over time?

Most hats stretch slightly with regular wear, especially those made from wool, cotton, or leather. Straw hats are more rigid. A hat that feels very slightly snug when new will typically conform to your head shape within a few wears. Avoid buying a hat that feels uncomfortably tight, though, as the stretch amount is limited to roughly 2-3 millimeters.