How to estimate Bambu filament usage per print.
Exact per-print filament usage is not always handed to you in a perfect historical report, but you can build a practical estimate by storing spool state before, during, and after print jobs.
Use spool state before and after the job
The simplest useful estimate comes from comparing the spool state at the start of a job with the state after the job completes. When that is stored consistently, you can see which rolls were touched and roughly how much each one changed.
Filter out rolls that were not actually used
Just because a roll is loaded in the AMS does not mean the print used it. A good history view only shows the spools whose state actually changed during that project.
Accept that the result is an estimate
For hobby workflows, an honest estimate is usually far more useful than no history at all. It is enough to understand which colors are disappearing, which materials are used most often, and how stock moves over time.