Your hat size is your head circumference in inches divided by π (3.1416), rounded to the nearest ⅛. A 22-inch head is a size 7, a 23½-inch head is a 7½, and a 25⅛-inch head is a size 8. Find your measurement in the chart below to get your fitted size, centimetres and the usual letter size.
Don't know your number yet? Measure your head in 2 minutes, or type it into the hat size calculator.
Hat size chart: 6½ to 8½
Every ⅛ of a hat size adds about ⅜ inch (1 cm) of head circumference. Most size charts stop at 7⅞ or 8. This one goes to 8½, because that's where our customers live.
| Hat size | Head (inches) | Head (cm) | Letter size / MONGO |
|---|---|---|---|
| 6½ | 20⅜ | 51.9 | XS |
| 6⅝ | 20⅞ | 52.9 | XS |
| 6¾ | 21¼ | 53.9 | XS–S |
| 6⅞ | 21⅝ | 54.9 | S |
| 7 | 22 | 55.9 | S |
| 7⅛ | 22⅜ | 56.9 | M |
| 7¼ | 22¾ | 57.9 | M |
| 7⅜ | 23⅛ | 58.8 | L |
| 7½ | 23½ | 59.8 | L–XL · MONGO fits |
| 7⅝ | 24 | 60.8 | XL · MONGO fits |
| 7¾ | 24⅜ | 61.8 | XL · MONGO fits |
| 7⅞ | 24¾ | 62.8 | XXL · MONGO fits |
| 8 | 25⅛ | 63.8 | XXL · MONGO fits |
| 8⅛ | 25½ | 64.8 | Past most charts · MONGO fits |
| 8¼ | 25⅞ | 65.8 | Past most charts · MONGO fits |
| 8⅜ | 26¼ | 66.8 | Past most charts · MONGO fits |
| 8½ | 26¾ | 67.8 | Past most charts · MONGO fits |
Letter sizes are a rough guide. There is no industry standard for S, M, L, XL. One general chart calls a 60 cm head "L"; MONGO calls 7½ the start of XL. New Era's stretch-fit L/XL covers 23⅞–24⅝ in, while Flexfit's L/XL covers 22⅜–23⅞ in. Always check the inches or centimetres, not the letter.
Why our cm numbers differ slightly from some brands: we calculate from the exact formula (size × π × 2.54). New Era rounds the inches first, so its 7½ is listed as 59.6 cm and ours as 59.8 cm. Same hat, same head, a 2 mm rounding difference.
How to read the chart
- Measure around your head, about a finger-width above your eyebrows and ears. Use inches or cm, whichever your tape has. (Step-by-step guide here.)
- Find the closest row. A 24-inch head is a 7⅝. A 62 cm head is a 7¾.
- For fitted hats, buy that number. For letter-sized or snapback hats, check the brand's own range in inches or cm.
What if you're between sizes?
Each size covers a band about ⅜ inch (1 cm) wide. If your tape lands right between two rows, go up a size. New Era gives the same advice for its fitted caps. A slightly loose fitted hat can be snugged up with sizing tape. A tight one stays tight, and that's how you get the red line on your forehead and the headache by 3 p.m.
| Your head | Between | Buy |
|---|---|---|
| 23⅜ in / 59.3 cm | 7⅜ and 7½ | 7½ |
| 23¾ in / 60.3 cm | 7½ and 7⅝ | 7⅝ |
| 24⅛ in / 61.3 cm | 7⅝ and 7¾ | 7¾ |
| 24½ in / 62.3 cm | 7¾ and 7⅞ | 7⅞ |
| 24⅞ in / 63.3 cm | 7⅞ and 8 | 8 |
| 25⅜ in / 64.3 cm | 8 and 8⅛ | 8⅛ |
With an adjustable snapback this matters less: you just pick a different snap.
Fitted vs letter sizes vs snapback
Fitted (7⅜, 7½, 7⅝…)
One closed size, no adjustment. Most accurate when the brand makes your size. The catch: most fitted lines stop at 8. New Era's 59FIFTY tops out at 8 (25 in / 63.5 cm). See the fitted hat size chart by brand for New Era, Flexfit and Richardson side by side.
Letter / stretch-fit (S/M, L/XL, XL/XXL)
A stretch band covers two or three fitted sizes. Comfortable when you're in the middle of the range, tight when you're at the top. Ranges vary a lot by brand, so read the inches.
Snapback / adjustable ("one size")
"One size fits most" usually means most people below about 7⅝. New Era's 9FORTY one-size cap fits 22–23⅞ in (55.8–60.6 cm). If you measure over that, you're wearing it on the last snap, if at all.
MONGO snapbacks are built for the other end: hat sizes 7½–8½, head circumference 23.6–26.7 in (60–68 cm), with a deeper crown so the hat actually sits down on your head instead of perching on top.
Kids and youth sizes
Kids' fitted hats generally run from about size 6 to 6¾. New Era lists its kids' 59FIFTY as 6 to 6¾ (48.2–53.9 cm). Measure a child the same way as an adult, and re-measure every season; heads grow. A size 6 is about 18⅞ in (47.9 cm), 6¼ is about 19⅝ in (49.9 cm), and 6½ is about 20⅜ in (51.9 cm).
Is your hat size big?
For context: in the US Army's ANSUR II survey (4,082 men measured), the median male head was 57.4 cm (about 22⅝ in, a 7¼) and the 95th percentile was 60.1 cm. That means a 7⅝ or larger head is bigger than about 95% of men. For women, the median was 56.0 cm and the 95th percentile 59.7 cm. More on this in average hat size for men and women.
Look up your exact size
Each of these pages covers the exact inch and cm range, how common the size is, the matching New Era, Flexfit and Richardson size, and which hats fit:
- 7⅜ hat size · 7½ · 7⅝ · 7¾ · 7⅞
- 8 hat size · 8⅛ · 8¼ · 8⅜ · 8½
Tools
- Hat size calculator: type in inches or cm, get your size.
- Printable hat size chart: print it, stick it on the fridge, settle the argument.
- How to measure your hat size: including the no-tape-measure method.
If you measure 23.6 inches or more
You're in MONGO range. The XL Performance Snapback 2.0 ($59.99, 7 colors) and the XL Foam Trucker both fit hat sizes 7½–8½ (60–68 cm). Free US shipping and a 30-day fit guarantee: if it doesn't fit, we cover the return shipping. Shop hats for big heads.
If you measure under 23.4 inches, you probably don't need an XL hat. A regular adjustable cap should do the job.
Hat size FAQ
How do I convert head circumference to hat size?
Divide your head circumference in inches by 3.1416 and round to the nearest ⅛. For centimetres, divide by 2.54 first. Example: 61 cm ÷ 2.54 = 24.0 in; 24.0 ÷ 3.1416 = 7.64, which rounds to 7⅝.
What hat size is 24 inches?
A 24-inch head is a size 7⅝ (about 61 cm). That's an XL in most letter sizing and bigger than about 95% of men's heads.
What hat size is 60 cm?
60 cm is about 23⅝ inches, which works out to a size 7½ (23.62 ÷ 3.1416 = 7.52). It's near the top of the 7½ band, so if a 7½ fitted feels snug, try a 7⅝.
What size is an XL hat?
It depends on the brand. XL usually means roughly 7½ to 7¾ (about 23½–24⅜ in, 60–62 cm), but some brands start XL lower. Check the brand's chart in inches or cm.
What is the biggest standard fitted hat size?
Most major fitted lines stop at 8. New Era's 59FIFTY tops out at size 8 (25 in / 63.5 cm). Above that, you need a brand that builds for bigger heads. MONGO snapbacks fit up to 8½ (26.7 in / 68 cm).
Should I size up or down if I'm between hat sizes?
Size up. A slightly loose hat can be snugged with sizing tape; a tight hat can't be fixed.