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Ready to discuss your custom hat project? Please fill out the form or email us at info@keystonehats.com. Our team will respond within 6 hours.
Ready to discuss your custom hat project? Please fill out the form or email us at info@keystonehats.com. Our team will respond within 6 hours.

Here’s our complete hat sizing chart. Use this guide to find your fit or convert between international sizes.Need help measuring your head first? Try our simple Hat Size Calculator.
Find your measurement in inches or centimeters to see your corresponding fitted and general size.
| Cm | Inches | US | EU | UK | Hat |
|---|---|---|---|---|---|
| 54-55 | 21.25-21.65 | 6⅞ | 54 | 6⅞ | XS |
| 56-57 | 22.05-22.44 | 7⅛ | 56 | 7 | S |
| 58-59 | 22.83-23.23 | 7¼-7⅜ | 58 | 7¼ | M |
| 60-61 | 23.62-24.02 | 7½-7⅝ | 60 | 7½ | L |
| 62-63 | 24.41-24.80 | 7¾ | 62 | 7¾ | XL |
| 64-65 | 25.20-25.59 | 8 | 64 | 8 | XXL |
Note: Most adjustable hats (baseball caps, trucker hats) are one-size-fits-most, fitting 56-61cm head circumference.
These have no adjuster and need to be the exact size. The chart above is most critical for this style.

These have no adjuster and need to be the exact size. The chart above is most critical for this style.

These are “one size fits most.” They have an adjustable snap on the back and typically fit head sizes from 22″ to 23 7/8″ (Medium to XL).

These hats have a flexible band. They usually come in combined sizes like S/M or L/XL. If you’re in between, it’s usually safe to go with the smaller size for a snug fit.
Kids’ heads grow fast. It’s always best to measure.
| Age | Cm | Inches | Size |
|---|---|---|---|
| 0-6 | 42-44 | 16.5-17.3 | Newborn |
| 6-12 | 44-46 | 17.3-18.1 | Infant |
| 1-2 | 46-48 | 18.1-18.9 | Toddler |
| 3-5 | 48-50 | 18.9-19.7 | Preschool |
| 6-10 | 50-54 | 19.7-21.3 | Youth |
| 10-14 | 54-58 | 21.3-22.8 | Teen |
Tip: Kids’ heads grow quickly – leave 1-2cm room for growth.
Choose the larger size. Hats can be tightened with adjusters, but small hats are uncomfortable.
Standards are similar but may vary slightly. Check specific brand size charts before buying.
Yes, some materials loosen slightly. Consider choosing a slightly snug fit initially.
Great. Now let’s get you the right hat. We make sure every hat we produce is built to last and feel comfortable.