Time-based pricing is intuitive and it misleads. The dominant cost of a print is the material it contains, and material scales with grams, not with hours.
A ten-hour print of a small delicate part uses less filament than a two-hour print of a solid block.
The hourly costs, priced
Electricity. A desktop printer averages roughly 100–150 W over a print — the hot end and bed cycle rather than running continuously. At 120 W and US average rates near 16 cents per kWh, that is about 2 cents an hour.
Nozzle wear. A brass nozzle lasts hundreds of hours with non-abrasive filament. Spread over its life, well under a cent an hour. Abrasive filaments — carbon fibre, glow-in-the-dark, glitter — change this sharply, and the answer there is a hardened nozzle rather than a wear allowance.
Belts, bearings, PTFE tube, build surface. Consumables replaced occasionally over hundreds of hours. Rounds to a couple of cents an hour on a well-used machine.
Depreciation. A $400 printer over 3,000 hours of use is about 13 cents an hour — and this is the largest hourly item by some distance, which surprises people who never counted it.
Total: somewhere around 15–20 cents per hour, and most of it is the printer wearing out rather than anything consumed.
Against material
A ten-hour print might use 100 g. At a $22 kg spool that is $2.20 of filament against roughly $1.70 of hourly costs.
So they are comparable — but only because depreciation is in there. Compare filament to electricity alone and material outweighs it by more than ten to one.
The arithmetic for material is in what a print actually costs.
The cost nobody prices
Failed prints. A 5% failure rate adds about 5% to material, and that understates it, because failures cluster near the end of long prints when the most filament has been laid down and the most hours spent.
A twenty-hour print failing at hour eighteen costs nearly full material and all the time. This is the largest real cost in hobby printing and it never appears in an hourly rate.
It is also why cheap unreliable filament is expensive filament.
If you are quoting someone else
Time genuinely matters here, because a machine printing for you is not printing for anyone else. A sensible quote is:
material + (hours × machine rate) + setup and post-processing labour
with the machine rate set by what you want the printer to earn rather than by what it costs. Post-processing — support removal, sanding, gluing — is frequently the largest labour item and the most often forgotten.
Reducing cost
In descending order of effect:
- Reduce failures. Dry filament, a level bed, a first layer that sticks.
- Fewer walls and less infill where strength is not needed — see where the grams go.
- Reorient to avoid supports. Support material is pure waste.
- Print overnight if your electricity has cheaper off-peak rates — worth about a cent an hour, which tells you how far down the list this belongs.
FAQ
How much electricity does a 3D printer use?
Roughly 100–150 W averaged over a print, or about 2 cents an hour at typical US rates.
What is the real cost of a 3D print?
Material dominates. A ten-hour, 100 g print costs about $2.20 in filament against roughly $1.70 in hourly costs, most of which is printer depreciation.
Should I price prints by hour or by weight?
By weight for material, plus an hourly machine rate if you are charging someone else for occupying the printer.
What is the biggest hidden cost in 3D printing?
Failed prints, especially long ones failing near the end. They cost nearly full material plus all the time.
Does printing overnight save money?
Only if your electricity is cheaper off-peak, and the saving is around a cent an hour.