Spool remaining calculator
The only accurate way to know what is left on a spool is to weigh it. Enter the total weight, the empty spool weight and the material to get the remaining filament in grams, metres and percent.
Empty spool weight varies: most 1 kg plastic spools are 150–250 g, cardboard spools 100–180 g. Weigh an empty one once and keep the number.
Why weighing beats guessing
Slicers cannot know what is physically left on your spool. A kitchen scale can. Weigh the whole spool, subtract the empty spool weight, and what remains is filament. The tool then converts grams to metres with the same density maths as the length converter.
Keep the empty-spool number for each brand you buy — it makes the reading exact in one step.
Related tools
Print cost calculator
Work out the real cost of a print and a selling price.
G-code analyzer
Drop in a .gcode file to get filament use, weight and cost.
Filament length & weight
Convert between metres, grams and cubic centimetres.
Volumetric flow calculator
Check whether your speed is more than the hotend can melt.
Print farm calculator
Model throughput and profit for one or many printers.
FAQ
How much does an empty filament spool weigh?
Typically 150–250 g for plastic 1 kg spools, and 100–180 g for cardboard. Weigh one when it runs out and note the figure.
Can I trust the percent reading?
It is accurate as long as the "full spool net weight" matches the spool you bought (some are 750 g or 1 kg) and you use the right empty-spool weight.