How the cost is worked out
Filament cost is the grams used, divided by the spool weight, times the spool price. Electricity is the average power in watts times the hours, divided by 1000 to give kWh, times your tariff. The total adds the two.
Every input is yours: the slicer reports grams and print time, the spool label gives its weight, and the electricity bill gives the tariff. The calculator stores nothing and sends nothing anywhere.
Failed prints, purge waste on multi-material machines, nozzle wear and the printer's own price are left out. Add the purge grams from the slicer to the filament figure if your printer changes colours.
For the reasoning behind the figures, see the filament types guide.
Questions
How do I work out what a 3D print costs?
Divide the grams the slicer reports by the spool weight and multiply by the spool price. Then add electricity: average watts times hours, divided by 1000, times your price per kWh.
Does electricity add much to the cost of a print?
Usually much less than the filament. At 100 W average for 2 hours and 0.25 per kWh, electricity comes to 0.05, against 0.50 for 25 g from a 20 per kg spool.
