Filament is the cost everyone counts. Electricity, printer wear, and the occasional spaghetti failure are the ones everyone forgets. Add them all up and price your prints fairly.
Filament used (g)
Print time (hours)
Spool price ($)
Spool weight (g)
Average draw while printing
Your rate ($/kWh)
For wear per hour; set 0 to skip
Your slicer reports grams used with good accuracy, including supports and purge. Divide spool price by spool weight for cost per gram — a $22 one-kilogram spool is 2.2¢ per gram — and multiply. This is usually the most exact line in the whole estimate.
The wattage options are averages over a whole print, not peak draw: heat-up spikes are brief, and the bed cycles on and off once at temperature. If you want your printer's true number, a $15 plug-in power meter over one long print gives you a personal average worth reusing.
Nozzles, belts, fans, PTFE tube, build surfaces, and eventually the machine itself are real costs that only show up when you divide printer price by expected lifetime hours. 3,000 hours is a reasonable midpoint for a consumer FDM machine that gets maintained; adjust to taste. Skipping this line is the most common way hobby sellers accidentally sell at a loss.
Some percentage of prints fail — adhesion lets go, supports collapse, filament tangles at 3 a.m. Spreading that cost across successful prints reflects what your output actually costs, the same way a bakery prices in the loaves that burn.