Hat Size Converter

Convert hat sizes between US fitted hat size, UK hat size, EU hat size, head circumference in inches, head circumference in centimeters, and general small, medium, large, and extra-large hat size references.

Convert Hat Size

22.5 inch head circumference is about US fitted size 7.16
Your hat size conversion result will appear here.

Common hat size conversions

Inches to centimeters:
cm = inches × 2.54

Centimeters to inches:
inches = cm ÷ 2.54

Head circumference to fitted size:
fitted size ≈ circumference ÷ π

EU hat size:
EU size ≈ head circumference in centimeters

Where hat size conversions are used

Hat size conversions are useful for fitted caps, baseball caps, cowboy hats, helmets, beanies, dress hats, sun hats, international sizing, online shopping, and converting head circumference between inches and centimeters.

Use this converter as an estimate, then compare your measurement with the brand’s size chart.

What your hat size result means

Your result shows the entered hat size or head circumference converted into the selected size system. The converter also displays approximate US fitted size, UK size, EU size, head circumference in inches, head circumference in centimeters, and general letter size.

Hat sizing can vary by brand, material, stretch, crown shape, brim style, hairstyle, and how snug or loose you prefer the hat to fit.

Hat size converter tips

Frequently asked questions

How do I measure my hat size?

Wrap a soft measuring tape around your head just above the eyebrows and ears. Use that circumference to estimate your hat size.

How do I convert head circumference to fitted hat size?

Divide head circumference in inches by pi. For example, 22.5 inches is about fitted size 7.16.

What is EU hat size based on?

EU hat size is usually close to head circumference in centimeters. For example, 57 cm is roughly EU size 57.

Are US and UK hat sizes the same?

They are very close for many fitted hats, but exact sizing can still vary by brand and style.

Are hat size conversions exact?

No. Hat size conversions are estimates because brands, materials, stretch, and fit preferences can vary.