Know your shelf.
Free filament inventory for 3D printing. Track every spool, deduct by weight when you print (drop your sliced g-code — grams auto-fill), weigh to correct, and restock honestly when your own rules say you're low.
Runs locally in your browser · no account · no cloud · your data never leaves your machine
Grams always carry their provenance: label · ✓ weighed · ≈ estimated core · ~ estimate · ? unknown. An estimate never masquerades as a measurement.
Log a print, the shelf deducts once — failed prints count too. Planned prints get "enough / short 120 g" verdicts before you start.
Weigh any spool; the gap vs the estimate becomes "unattributed usage" so untracked waste can't hide.
Set "keep 2 black PLA" once. When you dip below, it's on your Buy list with today's real first-party price — no fake urgency, ever.