Indicative conversions, not bank transaction rates.
An electricity estimate needs average power over the chosen duration, or measured energy directly. A power supply rating alone does not describe consumption throughout a job. The cost calculator requires an average in W, not a power supply capacity.
Do not mix three quantities
The EIA distinguishes watts from watt-hours: 1 kW = 1000 W, and 1 kWh is 1 kW sustained for one hour. For average P in W over t hours, E = P × t / 1000, in kWh.
| Input | Question it answers |
|---|---|
| Power supply rating | What capacity is specified for this equipment? |
| Instantaneous power | What power is drawn at this moment? |
| Average power over an interval | What constant power would use the same energy? |
| Accumulated energy, kWh | How much energy was used over the interval? |
Scope matters: printer alone, with dryer, lighting or other accessories. Do not compare readings with different equipment included.
A manufacturer’s example of the distinction
The official Original Prusa MK4S page states a 240 W power supply and consumption of 80 W with PLA settings and 120 W with ABS settings. These are manufacturer data for that machine; not all detailed conditions are shown. They are neither LayerBench3D measurements nor a guaranteed average for your print.
These coexisting numbers explain why automatically entering 240 W as average power can differ from the stated operation. They do not establish a universal scaling factor for power supplies.
Define the interval before measuring
If you have an energy meter suitable for the equipment, define start, end and included accessories. Record accumulated energy and duration over the same interval. Follow the meter manual and its limits; this article gives no electrical modification instructions.
If energy includes preheating but duration excludes it, the calculated average does not describe the intended interval correctly. Without measurements, use an identified assumption and compare scenarios rather than claiming an exact cost.
Reconstruct an average: theoretical example
Assume 0.66 kWh over 5.5 h, without claiming a printer was measured. Equivalent average power is 0.66 × 1000 / 5.5 = 120 W. At an also hypothetical EUR 0.30/kWh, cost is EUR 0.198, displayed separately as EUR 0.20.
Over the same duration and tariff, assumptions of 80 W and 160 W give respectively 0.44 kWh / EUR 0.132 and 0.88 kWh / EUR 0.264. This demonstrates input sensitivity, not real machine consumption.
The printing cost guide places electricity alongside filament cost and lists costs the tool excludes.
Sources consulted
- Measuring electricity — U.S. Energy Information Administration
Accessed - Original Prusa MK4S 3D Printer — Technical specifications — Prusa Research
Accessed