Hat Size
Find your hat size from head circumference in centimeters.
About Hat Size
The measured head circumference sets the numeric size and maps onto a standard letter band. A hat squeezed or floating is both uncomfortable and looks wrong, so the measurement matters.
Formula
Hat Size
cm = measured circumference; US = band from cm
- hat size num
- Head circumference around the brow ridge
Worked example
With the default values below, Hat Size returns Hat Size (cm) of 58. Change any input above and every figure here is recalculated in your browser.
Inputs used
- Head circumferenceminimum 40 cm
- 58 cm
Results
- Hat Size (cm)
- 58 cm
- US Size
- L
- Hat Size
- 22.8 in
Step by step
- 1Values used
- 2Hat Size
- 3Hat Size (cm)= 58 cm
- 4US Size= L
- 5Hat Size= 22.8 in
Assumptions and limits
- The result is derived only from the single input listed above. Anything not among them is not part of the calculation.
- In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
- Figures are rounded for display to 1 decimal place, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.
Frequently Asked Questions
How is Hat Size calculated?
cm = measured circumference; US = band from cm The measured head circumference sets the numeric size and maps onto a standard letter band.
Why does Hat Size matter?
A hat squeezed or floating is both uncomfortable and looks wrong, so the measurement matters.
What values do I need to enter?
This calculator takes 1 input: Head circumference. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.