How to Measure Your Head for a Ball Cap: Size Chart Guide

Wrap a soft tape around your head about 1 inch above the eyebrows and just above the ears, then match that number to the brand’s own chart.

Tape too high on the forehead means a cap that slides over your eyes.

Where The Tape Actually Goes

Measure head circumference at the hat’s resting line — about 1 inch (2.5 cm) above the eyebrows and just above the ears. That’s where a ball cap settles, so that’s the loop you size against.

Use a flexible soft tape; string works too — wrap it, mark the overlap, lay it flat against a ruler. Three details decide whether the reading is good:

• Level, not tilted. Keep the tape parallel to the floor all the way around.
• Snug, not tight. It should sit against your head without pressing in — pull tight and the number shrinks, giving you a cap that squeezes.
• Measure two or three times.

Write the number in both inches and centimeters. Most charts publish both, and metric travels better with brands sizing in cm.

Hat sizing isn’t standardized across brands. Two labels can both read 7 3/8 and fit differently, and the gap is widest with unstructured or “one size” caps, which Carhartt’s fit guide warns vary considerably by style. Always check the individual product’s chart.

Ball Cap Size Chart: Adult Fitted And Alpha Sizes

Letter sizing overlaps the fitted scale: small ~21 1/4–21 5/8 in (54–55 cm), medium ~22–22 3/8 in (56–57 cm), large ~22 3/4–23 1/8 in (58–59 cm), XL ~23 1/2–24 in (60–61 cm). Outdoor brands sometimes use their own bands — Arc’teryx splits adult hats into S-M at 55–57 cm and L-XL at 58–60 cm, with one-size styles covering 55–60 cm. That’s why the shop’s chart beats any general rule.

Between two sizes with no chart guidance, size up. A loose cap can be snugged with the rear strap or foam tape under the sweatband; a small one has nowhere to go. To see which models hold their shape after a season, our roundup of tested ball caps worth buying covers the ones that held up best.

Mistakes That Produce The Wrong Size

Three habits account for most bad orders, and all push the measurement the wrong way. Bristol’s head measurement guidance and Carhartt’s fit notes point to the same fix: a level, relaxed tape on the hat’s natural line.

• Taping too high.
• Taping too low.
• Yanking the tape tight. Compression shaves the reading; the band digs in.

Kids’ headwear is separate — those charts scale down and should never be matched to the adult fitted numbers above. Use the manufacturer’s kids’ chart for that hat.

Ready to order? Re-check the product’s own sizing table, since a 23-inch head can be a large in one brand and a medium in another. Note the confirmed number in your phone, and future purchases become a ten-second lookup instead of a return.