Chainmail ID and WD Finder
This calculator is used when you know what AR you need, but not sure what size wire or inner diameter of ring you need to get the AR you want.

You can press TAB on your keyboard to move to the next field.

Desired AR *
Ring's Inner Diameter (ID)
Wire's Diameter (WD)

This tool was originally made by abnoba12, that's his username over on the M.A.I.L. forums. He made it purely for the sake of the chainmail community. So I've setup a mirror of the tool here.