WattsyHow it works
Subtract the empty spool's weight from the current weight to get the grams of filament left. To turn grams into meters, the calculator divides by the material's density to get its volume, then divides by the cross-section of the filament. That's why the same weight of ABS is longer than PLA — ABS is lighter per centimeter.
How long is a 1 kg spool?
| Material (1.75 mm) | Length of 1 kg |
|---|---|
| PLA | about 335 m |
| PETG | about 327 m |
| ABS | about 400 m |
| ASA | about 389 m |
| TPU | about 344 m |
Frequently asked questions
How do I know how much filament is left without a scale?
You can estimate by eye from how deep the filament sits on the spool, but it's rough. A cheap kitchen scale is the reliable way, accurate to a few grams.
How much does an empty spool weigh?
It varies by brand: plastic spools are usually around 150–280 g and cardboard spools around 100–150 g. Weigh an empty spool from the same brand once and reuse that number.
What if I run out mid-print?
Many printers can pause on filament runout so you can load a new spool. Otherwise, splitting the job across two spools of the same color works if you swap carefully at a layer change.