Sizing & Styling · Updated 2026-05-12
How to Measure Your Head for a Flat Cap
Flat caps and scally caps are sized by head circumference, not by S/M/L alone. Get the measurement right and almost any maker's chart will land you in the correct size on the first try. You only need a soft tape measure (or a length of string and a ruler) and about thirty seconds.
What you need
A soft cloth tape measure is ideal. If you don't own one, wrap a piece of non-stretch string around your head, mark where it overlaps, then lay it flat against a ruler.
Measure with your hair styled the way you normally wear it. Wet hair, a fresh haircut or a man-bun all change the number by half a size.
Where to put the tape
Place the tape across the middle of your forehead — about one finger-width above your eyebrows — then run it around the widest part of the back of your head, just above the ears. This is the line where a cap actually sits.
Keep the tape level all the way around. Snug, but not tight: you should be able to slide a fingertip underneath it. Take the measurement twice and use the larger number.
Size chart
Most makers publish their own chart, but this is the conversion almost all of them are within a few millimetres of:
Hatters in the US sometimes still use fitted sizes (6⅞, 7, 7⅛). Roughly: 6⅞ = 55 cm, 7 = 56 cm, 7⅛ = 57 cm, 7¼ = 58 cm, 7⅜ = 59 cm, 7½ = 60 cm.
Between two sizes? Size up.
Wool and tweed will shrink slightly the first time they get caught in the rain, and a tight wool cap pinches above the ears within an hour. The exception is unlined leather caps, which stretch about half a size with wear — for those, size down.
If a maker offers a fitted (non-elasticated) and an adjustable version of the same cap, the adjustable one is more forgiving when you're between sizes.
Style-specific notes
Scally caps and ivy caps fit close to the head, so accuracy matters most here. Newsboy and baker boy caps have a fuller crown that hides half a centimetre either way. Driver caps run small because of their unlined, snug-fit design — measure carefully and consider sizing up.
Common questions
- What if my head is between two sizes?
- Size up. Wool and tweed shrink slightly with rain and dry-cleaning, and a snug cap becomes uncomfortable above the ears after an hour. The only exception is unlined leather, which stretches with wear — size down for those.
- Do I measure with hair up or down?
- Wear your hair the way you normally wear it. A fresh haircut or wet hair will shift the number by half a size.
- How tight should the tape be?
- Snug but not constricting — you should be able to slide a fingertip under the tape. If it leaves a mark on your forehead, it's too tight.
- Why do my caps slide forward over my eyes?
- The cap is half a size too large, or the crown shape is wrong for your head (long-oval vs round-oval). Try a maker who offers a 'long oval' option, or look for caps with an internal sweatband that grips.