It is a web tool to convert hat sizes from a measurment system to another.
Browsing the Hat size conversion site means you want to buy a hat,
but you don't know which size fit for you. Hat size conversion tool will help you to find out the right hat size, just follow the steps below.
So you have to know your hat size in minimum one sizing system.
If you don't know your hat size, there are several tutorials, step-by-step instructions on the internet.
You just have to write "How to Determine Your Hat Size" in Google.
After choosing the target hat sizing system, the converted size will appear in the grey input box.
If you modify any parameter of the hat size conversion, the result of the new conversion will be calculated automatically.