Measure your head circumference where the cap will sit, then match that number to the brand’s size chart for the exact model.
The right cap size for men starts with one number: the circumference of your head where the cap actually rests. That spot is the widest part — roughly above the eyebrows and ears. Once you have that measurement in inches or centimeters, you compare it against the specific brand’s chart, because size labels are not standardized across manufacturers.
Measuring Your Head for a Cap That Fits
Grab a soft tape measure. Wrap it around your head at the level where the cap will sit — about a finger’s width above the eyebrows, running just over the ears. Keep the tape level and snug, not tight, and note the circumference.
Read the number twice. Measuring too high or too low on the forehead, or pulling the tape tight, throws the result off by enough to land you in the wrong size.
Fitted vs. Adjustable: The Two Sizing Systems
Fitted caps use numbered sizes that correspond directly to head circumference. If your measurement falls between two sizes, fitted caps generally follow the exact chart number rather than rounding up.
Adjustable caps offer more forgiveness. The strap or closure lets you fine-tune the fit after purchase.
Matching Your Measurement to a Size
Most brands publish a simple conversion. Under Armour’s chart maps fitted cap sizes to head circumference like this:
| Fitted Cap Size | Head Circumference |
|---|---|
| 6 5/8 | 20 7/8 in / 53 cm |
| 7 | 22 in / 55.9 cm |
| 7 1/4 | 22 3/4 in / 57.8 cm |
| 7 1/2 | 23 1/2 in / 59.7 cm |
Several manufacturers cluster adult cap sizes around 53–65 cm head circumference, with larger sizes at the upper end. If your measurement sits at the top of one size and the bottom of the next, adjustable caps are the safer pick since the band gives you room to adjust.
Brand Size Charts Are Not Interchangeable
A nominal size like 7 can map to slightly different inch and centimeter ranges depending on the manufacturer. Nike’s hat sizing, Under Armour’s headwear chart, and New Era’s fitted cap guide each use their own tables. Always check the specific brand’s chart for the exact cap model you want, rather than trusting a size that fit you in another brand.
When your measurement lands between sizes and you’re buying a fitted cap, the chart number is your answer. For adjustable caps, the closure compensates for small differences, so a one-size range that covers your number will typically work fine. If you’re still weighing options, our roundup of the best caps for men breaks down top picks by style and fit.
FAQs
What if my head measurement falls between two cap sizes?
For fitted caps, stick with the exact chart size closest to your measurement, since these have no adjustment mechanism. For adjustable caps, either size range that includes your number works, because the strap or closure gives you room to fine-tune the fit after you put the cap on.
Do cap sizes run the same across all brands?
No. Size labels are not standardized, so a size 7 in one brand can map to slightly different head circumference ranges in another. Always reference the specific manufacturer’s chart for the exact cap model you’re buying, and measure your head fresh rather than trusting an old size you remember.
Should I measure my head with the tape tight or loose?
Measure snug but not tight. Pull the tape until it touches your head evenly without compressing the skin, and keep it level all the way around. A tight measurement gives you a cap that feels small, while a loose one leaves you with a cap that slips or sits too high.
References & Sources
- Nike. “Hats & Headwear Size Guide.” Lists fitted cap sizes from 6 1/2 to 8 and measurement guidance.
- Under Armour. “Men’s Headwear Size Chart.” Maps fitted sizes to inch and centimeter head circumference values.
- New Era. “Fitted Caps Size Guide.” Provides adjustable and fitted cap sizing details for men.
- Stormy Kromer. “Size Chart.” Maps head circumference from 52 to 64 cm across fitted sizes 6 1/2 to 8.