How the conversion works
Every game turns mouse movement into a camera angle with its own constant, often called the yaw value. When you multiply your sensitivity by the yaw value, you get how many degrees the camera turns for each count your mouse reports. To keep the same feel, the converter keeps that angle the same in both games and solves for the new sensitivity. DPI cancels out, so you can use the same mouse in both games.
What is cm per 360?
It is the distance you move the mouse to turn all the way around. It is the easiest number to compare between players and games. A lower sensitivity means a longer distance.
Good to know
The yaw values come from community-documented game settings and are widely used by converters. Zoom and scope sensitivity, field of view and raw input settings can still make a game feel different, so test the result in an aim trainer and adjust by small steps.