Calculator: https://gavinfw.github.io/PAX/
https://gavinfw.github.io/PAX/example.html
PAX, or the Professional Autocross Index, is used to compare the performance of autocross racecars which may be built to very different class standards. This calculator is for making PAX comparisons quickly and easily.
While very capable, this calculator is designed to be constrained in a small window or embedded banner.
When the window grows to a square, a number pad appears allowing fast entry into the single input field.
On a phone, landscape orientation reveals the calculator output for each class.
Switching to a portrait enlarges the buttons and also exposes historical PAX figures and customization.
While this is somewhat of an advanced tool not aimed at new autocrossers, it does aim to be self explanatory in a way that gives insight into autocross classes and categories. The historical PAX figures also serve as a reference.