Electricity is usually the smallest line in a 3D print's cost. This guide gives you the formula, a cost-per-hour table you can read off, and a way to measure your own printer instead of trusting a spec sheet.
The Formula
Watts x hours / 1000 x your rate per kWh = electricity cost
The 3D Print Cost Calculator uses the same formula: energy cost = (watts x print hours) / 1000 x rate.
Worked example: a printer averaging 120 W for 5 hours.
120 x 5 / 1000 = 0.6 kWh. At 18.31 cents/kWh that is 0.6 x 0.1831 = $0.11.
Which Rate to Use
The US average residential price was 18.31 cents/kWh in July 2026, according to the U.S. Energy Information Administration (preliminary estimate): EIA Electric Power Monthly, Table 5.6.A. The same table shows a range by state, from 12.72 cents in Louisiana to 48.00 cents in Hawaii for that month.
Rates change monthly, so use the number on your own utility bill (cents per kWh, or dollars per kWh divided by 100) when you have it. The calculator defaults to $0.15/kWh and 200 W, so replace both with your own figures.
What Wattage Does a Printer Draw?
A printer's rated power is a maximum, not what it averages over a print. The heated bed and hot end cycle on and off, so the average is lower than the label on the power supply.
One published figure to anchor on: the Original Prusa MK4S is listed with a 240 W power supply and an expected consumption of about 80 W when printing PLA and about 120 W for ABS (figures repeated by a retailer, 3DJake MK4S page; not checked against Prusa's own page). Other printers differ, and enclosed, large-bed or high-speed machines can draw more.
The reliable method is to measure it. Plug the printer into a plug-in watt meter (a kill-a-watt style meter), run a typical print, and read the kWh total. Divide kWh by print hours to get your real average watts.
Cost Per Hour at Common Wattages
Computed at 18.31 cents/kWh (watts x 0.1831 / 1000):
| Average draw | Per hour | 10-hour print | 100 hours | |--------------|----------|---------------|-----------| | 80 W | $0.015 | $0.15 | $1.46 | | 120 W | $0.022 | $0.22 | $2.20 | | 200 W (calculator default) | $0.037 | $0.37 | $3.66 | | 350 W | $0.064 | $0.64 | $6.41 |
The 350 W row is an upper-bound case, not a typical average.
The same 200 W printer at the state extremes from the EIA table (12.72 and 48.00 cents/kWh) costs $0.025 and $0.096 per hour.
Monthly and Yearly Cost at 120 W
At 120 W and 18.31 cents/kWh:
| Use | Hours/month | kWh/month | Monthly | Yearly | |-----|-------------|-----------|---------|--------| | Light | 10 | 1.2 | $0.22 | $2.64 | | Active | 40 | 4.8 | $0.88 | $10.55 | | Heavy | 100 | 12 | $2.20 | $26.37 |
Even at 100 print-hours a month, electricity is about $2.20 for a 120 W printer.
Example Print Costs
Same rate, with the wattage and time assumed for each row:
| Print | Time | Assumed draw | kWh | Electricity | |-------|------|--------------|-----|-------------| | Small keychain | 1 h | 80 W | 0.08 | $0.01 | | Phone case | 3 h | 80 W | 0.24 | $0.04 | | Large bowl | 8 h | 100 W | 0.80 | $0.15 | | Functional part, hotter bed | 6 h | 180 W | 1.08 | $0.20 | | Overnight vase | 12 h | 90 W | 1.08 | $0.20 |
The wattages are illustrative assumptions, not measurements of those parts.
Things That Raise Power Draw
- Bed and nozzle temperature. Materials that need hotter beds and nozzles draw more. Check your filament maker's datasheet for the recommended temperatures, and the printer manual for its limits.
- Enclosures and heaters. An active chamber or enclosure heater adds to the total; measure it with the watt meter rather than guessing.
- Print duration. Time multiplies everything, so faster profiles with acceptable quality cut energy as well as hours.
- Failed prints. The calculator adds a flat 10% buffer on total cost to cover failures; track your own failure rate and replace that figure when you have data.
Reducing Electricity Cost
- Fill the bed with several parts per run so the heating phase is shared.
- Keep layer height and infill no higher than the part needs.
- If your utility offers time-of-use pricing, ask for the off-peak rate and check whether it applies to you.
Where Electricity Fits in the Total
At 200 W, a 5-hour print costs about $0.18 in electricity at the 2026 average rate. Filament, machine wear and your own time usually outweigh it, which is why the calculator also takes filament cost and printer price. See the 3D print cost breakdown for the full formula.
Key Takeaways
- Electricity cost = watts x hours / 1000 x rate.
- US average residential rate: 18.31 cents/kWh (EIA, July 2026, preliminary). State range that month: 12.72 to 48.00 cents.
- Measure your printer with a plug-in watt meter instead of relying on rated wattage.
- At 120 W, 100 hours a month costs about $2.20.
Ready to run your own numbers? Try our free 3D Print Cost Calculator.