This CR Calculator has been developed as a tool so you can input item levels and generate your CR.
How does it work?
Overall CR is calculated with the highest level gear for that slot regardless of whether it is equipped, in your inventory, or in your bank. Utility belts and trinkets occupy the same slot so you should enter whichever is highest, even if the trinket is equipped in a utility belt slot.
The game also now displays a currently equipped CR which only uses the information of gear your character is currently wearing.