Cap sizing looks simple until you buy a cap that measures right and still sits wrong. This guide covers the measurements that matter beyond circumference.
Measure the head correctly
Wrap a soft tape around the head, just above the ears and across the middle of the forehead. Keep it level and snug without pressing. Take the measurement twice; if they differ, use the larger number.
Circumference is only one number
Two people with the same circumference can have very different crown depths. A rounder head needs a deeper crown; a flatter crown on a round head sits high and looks small. This is why two caps in the same size can feel completely different.
Crown depth and profile
Low-profile crowns suit flatter heads and shorter faces. High-profile crowns suit rounder heads and taller faces. If a cap sits above your hairline and slides, the crown is probably too shallow, not too small.
Brim curve
A pre-curved brim frames the face and is forgiving. A flat brim on a fitted cap can look wide on a narrow face. Brim width is fixed by the model, so try the shape before judging the size.
When to size up or down
Size up if the cap leaves marks on the forehead or feels tight at the temples after ten minutes. Size down if the cap slips when you look down. Between sizes, choose the larger one for fitted caps and rely on the strap for snapbacks.
Cap sizing varies by brand and model. Check the specific size chart on the product page. Paid links on this site may earn us a commission.