Height tool

Hat size calculator

Estimate hat size from head circumference in centimeters or inches.

Head circumference, cm Sex

Head circumference	Letter	US	UK

Measure around the widest part of the head, slightly above the eyebrows. Hat shape and hair volume can change the best fit.

How it works

The calculator maps head circumference to common EU, US, UK, and letter hat sizes.

If your measurement lands between two rows, the larger size is usually the safer starting point.

Hat sizing varies by brand, material, crown shape, and preferred tightness.

Where should I measure head circumference?

Measure around the widest part of the head, above the eyebrows and ears.

What if I am between sizes?

Start with the larger size, especially for structured hats.