Hat Size Calculator
Measure round your head where the hat band sits, in centimetres or inches. The calculator gives your US fitted size, UK size, European size and letter size from XS to XXL.
- US, UK and EU
- Letter sizes
- Fitted caps
Measure about 1 cm above your eyebrows and ears with a soft tape, snug but not tight.
Hat sizes all come from the head measurement. European sizes are just the measurement in centimetres. US sizes are the measurement in inches divided by pi, to the nearest eighth, and UK sizes are one eighth smaller. A 57 cm head is a US 7 1/8.
Hat size chart
Fitted hats and caps. Search for a head size.
| Head (cm) | Head (in) | US | UK | Letter |
|---|---|---|---|---|
| 54 | 21.3 | 6 3/4 | 6 5/8 | XS |
| 55 | 21.7 | 6 7/8 | 6 3/4 | S |
| 56 | 22 | 7 | 6 7/8 | S |
| 57 | 22.4 | 7 1/8 | 7 | M |
| 58 | 22.8 | 7 1/4 | 7 1/8 | M |
| 59 | 23.2 | 7 3/8 | 7 1/4 | L |
| 60 | 23.6 | 7 1/2 | 7 3/8 | L |
| 61 | 24 | 7 5/8 | 7 1/2 | XL |
| 62 | 24.4 | 7 3/4 | 7 5/8 | XL |
Letter sizes vary a little between makers. Use the cm or US size where you can.
Head size and hat size
US, UK and EU. Slide the head size.
The drawing shows the tape at the height where the hat band sits.
How to measure for a hat
Tape round the head. Step through it.
Use a soft tape
Or string and a ruler.
Measure twice. Hair styles and thick hair can change the size by half a size or more.
Fitted, adjustable or knit
Hat types. Compare them.
Exact size, no strap.
Strap or snap back.
Stretches to fit.
Felt and straw hats do not stretch much, so fit matters most for them.
Before buying
Fit checks. Tick each item.
Tick each item as you go.
Between sizes, choose the larger and add a foam sizing strip behind the band.
What you get
Hat sizing. Each tile explains one result.
Fitted caps too.
One eighth smaller.
Head in cm.
XS to XXL.
cm and inches.
Children's heads reach about 90% of adult size by age 6, so kids' hat sizes change slowly after that.
Frequently Asked Questions
No question matches that search.
How do I find my hat size?
Measure round your head in cm. That is your EU size. Divide inches by 3.14 for the US size.
What hat size is 57 cm?
US 7 1/8, UK 7, letter M.
What is the average hat size?
About 57 to 58 cm, US 7 1/8 to 7 1/4.
Is UK hat size the same as US?
No, UK is one eighth smaller for the same head.
What if I am between hat sizes?
Go up a size and add a sizing strip.
What size is a large hat?
About 59 to 60 cm, US 7 3/8 to 7 1/2.
Do fitted caps use the same sizes?
Yes, they use US eighths.
A hat that stays put
Measure where the band sits and convert to the sizing your hat maker uses. You get a hat that fits snugly without pressing.
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