Quick answer: The average hat size for a man is about 7¼, from a head circumference of roughly 22⅝ inches (57.4 cm). For a woman it's about 7, or roughly 22 inches (56.0 cm). Those are the medians from ANSUR II, the US Army's 2012 survey that measured more than 6,000 adults. A head of 23.6 inches (60 cm, size 7½) or more is around the 95th percentile. That's where "big head" starts, and it's where MONGO's sizing starts too.
Shop hats built for sizes 7½–8½
Every MONGO hat has a deeper crown and an extended-range snapback that fits head sizes 7½ through 8½ (60–68 cm). 30-day fit guarantee: if it doesn't fit, return shipping is on us.
XL Performance Snapback 2.0 · XL Foam Trucker · See all hats for big heads →
Is my head big? Find your measurement
Find your head circumference in the left column. The hat size is the circumference in inches divided by π, rounded to the nearest ⅛. The percentile tells you what share of adults in ANSUR II have a smaller head than yours.
| Head circumference | Hat size | Approx. percentile (men / women) | Verdict |
|---|---|---|---|
| 21 in / 53.3 cm | 6⅝ | under 1st / ~6th | Small. Standard caps fit with room to spare. |
| 22 in / 55.9 cm | 7 | ~17th / ~47th | Below average for a man, about average for a woman. |
| 23 in / 58.4 cm | 7⅜ | ~73rd / ~86th | Above average but not big. Standard caps should fit. |
| 23.5 in / 59.7 cm | 7½ | ~92nd / ~95th | Borderline big. At the top of standard sizing. MONGO's range starts at 23.6 in, so measure again. |
| 24 in / 61.0 cm | 7⅝ | ~98th / ~99th | Big. MONGO fits. |
| 24.5 in / 62.2 cm | 7¾ | above 99th / above 99th | Big. MONGO fits. |
| 25 in / 63.5 cm | 8 | above 99th / above 99th | Very big. MONGO fits. |
| 26 in / 66.0 cm | 8¼ | above 99th / above 99th | Very big. MONGO fits (up to 26.7 in / 68 cm). |
How we got the percentiles: ANSUR II publishes the 5th, 50th and 95th percentiles for head circumference. For men those are 54.8, 57.4 and 60.1 cm, and for women 53.2, 56.0 and 59.7 cm. We estimated the in-between values from those three points, assuming a normal bell curve. Treat the results as approximate. ANSUR II measured soldiers, and the tape went over their hair. Above the 99th percentile the survey has too few people to rank more finely.
Average hat size at a glance
| Group | Average (median) hat size | Average head circumference | Middle 90% of adults |
|---|---|---|---|
| Men | 7¼ | 22⅝ in / 57.4 cm | 21⅝–23⅝ in (54.8–60.1 cm), sizes 6⅞–7½ |
| Women | 7 | 22 in / 56.0 cm | 21–23½ in (53.2–59.7 cm), sizes 6⅝–7½ |
If you've seen 57 cm in one place and 58 cm in another as the "average adult male head circumference," both are about right. ANSUR II's median for men is 57.4 cm, and a separate NIOSH sample of US civilian men averaged 57.6 cm. Either way it rounds to a hat size of 7¼, with 7⅜ just above it.
What counts as a big head?
If you measure 7½ or above (23.6 in / 60 cm+), your head is bigger than about 95 in 100 men's, and you've probably noticed most hats don't fit right. That's not a problem with your head. Most "one size fits all" and standard fitted hats top out around 7⅝. As they get bigger they add width but not crown depth, so on a big head the hat perches on top instead of sitting down properly.
Big-head sizes generally run from 7½ up to 8½ (about 60–68 cm). If you're in that range, you're not alone. You just need a hat actually built for it.
Is 23 inches a big head? Is 24 inches?
23 inches (58.4 cm) is a hat size 7⅜. It's above average, bigger than roughly 7 in 10 men, but it isn't a big head. Standard caps are built for it, so you probably don't need an XL hat.
24 inches (61 cm) is a hat size 7⅝, bigger than roughly 98 in 100 men and 99 in 100 women. That is a big head. Most "one size" caps will be at their last snap or won't close at all, and this is squarely where MONGO fits.
How to find your own hat size
Wrap a soft tape measure (or a piece of string) around your head about an inch above your ears and eyebrows. Read the measurement in inches and match it to a chart. Our big head hat size guide walks through it step by step. Or type your measurement into the hat size calculator, or print the printable size chart.
Where above-average heads go
MONGO hats are built specifically for sizes 7½ to 8½ (23.6–26.7 in / 60–68 cm). They have a deeper crown and an extended-range snapback, so an above-average head gets a hat that fits like it should. If you measure under 23.6 inches, you probably don't need us, and that's fine. Shop XL hats for big heads →
FAQ
What is the average hat size for a man?
About 7¼. The median adult male head in the ANSUR II survey is 57.4 cm (22⅝ inches) around, and 9 in 10 men fall between 6⅞ and 7½.
What is the average hat size for a woman?
About 7. The median adult female head in ANSUR II is 56.0 cm (22 inches) around, and 9 in 10 women fall between 6⅝ and 7½.
Is 23 inches a big head?
No. 23 inches (58.4 cm) is a size 7⅜. It's above average, bigger than roughly 7 in 10 men, and standard caps are made to fit it.
Is 24 inches a big head?
Yes. 24 inches (61 cm) is a size 7⅝, bigger than roughly 98% of men and 99% of women. Most one-size caps won't fit it comfortably.
What is considered a big head?
Roughly 23.6 inches (60 cm), hat size 7½, and up. That's about the 95th percentile for both men and women in ANSUR II.
Is a 7¾ a big head?
Yes. 7¾ is about 24⅜ inches (62 cm) around, above the 99th percentile, and most standard hats don't offer it.
Shop hats built for sizes 7½–8½
Every MONGO hat has a deeper crown and an extended-range snapback that fits head sizes 7½ through 8½ (60–68 cm). 30-day fit guarantee: if it doesn't fit, return shipping is on us.
XL Performance Snapback 2.0 · XL Foam Trucker · See all hats for big heads →
Sources
ANSUR II head circumference percentiles (5th / 50th / 95th): ANSUR II Data Explorer · Survey overview: Penn State OPEN Lab, ANSUR II · ANSUR II means and measuring method: HatSizeCharts, Real World Appeal (includes the NIOSH civilian comparison)