3D Print Energy Cost Calculator
Preheat duration, energy per job, and running cost at your own tariff. Everything is computed in your browser and nothing is sent anywhere.
Costs are in whatever currency you entered the tariff in. Monthly figure assumes 4.33 weeks.
How to get the average wattage
This is the input that decides the answer, and nameplate wattage is not it. A printer's power supply is sized for the worst case, which is the bed and hotend heating from cold at the same time. Once the machine reaches temperature both heaters duty-cycle, so the average over a long job is typically a fraction of the rated figure. Bed size and whether the printer is enclosed matter more than anything else.
The reliable way to fill this field in is a plug-in energy meter left on the socket for one full job; it reports total kWh, and dividing by job hours gives the average watts to enter here. Failing that, start from a figure someone has published for the same model of printer, and treat the result as an order of magnitude rather than a bill.
Host draw is separate because the host runs whether or not a print is going. A small single-board computer with a camera attached sits in the low single-digit to low double-digit watt range; a repurposed desktop does not.
What the preheat estimate does and does not model
The preheat figure is a simple linear approximation of heat-up time against the temperature rise required from your stated room temperature, with the bed weighted far more heavily than the hotend because it has vastly more thermal mass. It deliberately ignores bed material and thickness, heater wattage, mains voltage, enclosure, and draughts, all of which move real numbers around. Use it to compare scenarios, not to time anything precisely.
The energy figure is the more trustworthy of the two, because it is driven by a value you measured rather than a value the tool guessed.
Related reading
- OctoPrint Raspberry Pi setup: hardware and first boot covers picking the host and supply that this calculator's host-draw field describes.
- OctoPrint remote access covers Tailscale, WireGuard, an authenticated proxy and OctoEverywhere.
- OctoPrint disconnects mid-print is the diagnostic order when a long job dies partway through.
- OctoPrint vs Klipper compares the two host stacks before you commit to either.