Running out of filament mid-job, or buying a spool you already had, costs money and time. A simple tracking system fixes both.
What to track for each filament
| Field | Example |
|---|---|
| Material | PETG |
| Brand | (your brand) |
| Colour | Black |
| Spool size | 1,000 g |
| Price paid | $30 |
| Cost per gram | 3.0¢ |
| Grams remaining | 640 g |
| Full spools in stock | 2 |
| Reorder point | 1 full spool |
| Storage location | Dry box 2 |
| Opened / last dried | Sept 12 |
Track each kind of filament as one line (material, brand, colour, spool size), with the number of full spools plus the grams left on the open one.
How to know what's left on a spool
Weigh it. Kitchen scales work fine.
Grams remaining = spool weight on the scale − empty spool weight
The empty spool weight varies by brand (often around 150–250 g for plastic spools). Weigh an empty one from each brand once and write it down.
Keeping stock up to date
The hard part isn't setting up a list. It's keeping it right.
- After each job: subtract the grams used (from your slicer, plus waste).
- When a spool arrives: add it straight away.
- Once a month: weigh your open spools and correct any drift.
Set reorder points
Decide the minimum you want on hand for each filament you use regularly, such as one full spool plus the open one. When you drop below it, reorder. Allow for shipping time, especially for less common materials.
Don't forget supplies
The same method works for everything else your products use: nuts, bolts, magnets, heat-set inserts, boxes, labels, and bags. Track the quantity on hand and the cost of each, and include them in your product costs.
Store filament properly
Many filaments absorb moisture, which causes stringing and weak prints. Keep open spools in sealed containers with desiccant, note when each spool was last dried, and use older stock first.
When a spreadsheet stops working
A spreadsheet is fine for a handful of spools. It gets hard to keep up when you have dozens of colours, several printers, and jobs finishing every day, because every job means updating several rows by hand.
In Nozzlet Works, filament and supplies are deducted automatically when a job is marked complete. Importing your existing spreadsheet is coming, to make getting started quicker.