What Does It Cost to Run a 3D Printer? The Real Electricity Math

"Electricity is basically free, right? It's just a bit of plastic and some power." That's the assumption behind almost every underpriced 3D print. The electricity for a single print really is cheap — but it is not zero, and across a month of long prints or a small print farm it adds up to a line on your bill that someone has to pay. The question is whether that someone is you or your customer.

This article gives you a dead-simple formula for the electricity cost of any print, shows why the heated bed matters more than the hotend, and works through real examples.

The only formula you need

Electricity is sold in kilowatt-hours (kWh). To find what a print costs, you need three numbers:

energy (kWh) = average power (watts) × print time (hours) ÷ 1000
cost = energy (kWh) × your electricity rate (per kWh)

That's it. The whole game is estimating average power correctly, because the other two numbers you already know (your slicer gives you the print time, and your utility bill gives you the rate).

Why "average power" is lower than the printer's rating

Here's the mistake people make: they read "350W power supply" on the printer and assume it draws 350W the whole time. It doesn't.

A printer pulls its peak wattage only during heating — warming the bed and hotend at the start, and topping them up during the print. Once it's at temperature, it sips power to hold heat and move motors. So the average draw over a full print is much lower than the peak.

For most desktop FDM printers, real-world average draw lands in these ranges:

The single biggest variable is the heated bed. A large bed at 60 °C for PLA is manageable; the same bed at 100 °C for ABS can double your average draw. Bed size and bed temperature drive your power bill far more than the hotend does.

Worked examples

Let's use a US-ish rate of $0.17/kWh (the national average hovers here in 2026, but rates range from about $0.10 to over $0.40 depending on where you live — use your rate).

A small keychain, Bambu A1, 1 hour, PLA, ~90 W average:

0.090 kW × 1 h = 0.090 kWh
0.090 kWh × $0.17 = $0.015  →  about 1.5 cents

A medium model, Bambu A1, 8 hours, PLA, ~100 W average:

0.100 kW × 8 h = 0.8 kWh
0.8 kWh × $0.17 = $0.136  →  about 14 cents

A big multi-part order, enclosed printer, 24 hours, ABS, ~200 W average:

0.200 kW × 24 h = 4.8 kWh
4.8 kWh × $0.17 = $0.816  →  about 82 cents

See the pattern? Per print it's pennies to under a dollar. But run that 8-hour PLA print every day for a month and you're at roughly $4 — and a small farm of five printers doing the same is $20/month in electricity you're probably not charging for.

Should you even bother charging for it?

Yes — but proportionately. Electricity is rarely your biggest cost, but leaving it out is a symptom of the deeper problem: pricing by filament weight alone and ignoring everything else. The honest approach is to include it as one small, explicit line rather than pretending it's free.

There are two ways to handle it:

1. Per-print (accurate): use the formula above for each job. Best when print times vary a lot.
2. Flat add-on (simple): if your prints are similar, fold a flat figure (say $0.15–$0.50) into every order and move on.

Measuring your real numbers

If you want to stop guessing average wattage, a $15 plug-in energy meter (a "Kill A Watt" style device) sits between the printer and the wall and shows actual kWh consumed over a print. Run a few typical jobs, read the kWh, and you'll have your real average draw instead of a table estimate. It pays for itself the first time it stops you from under-pricing a long ABS print.

Where this fits in your price

Electricity is one of seven costs in every print — material, electricity, machine wear, failure buffer, labour, packaging and profit. On its own it's small; the danger is treating "small" as "skip it," because the same logic quietly drops machine wear, failed prints and your own labour too, and those are the costs that sink a 3D-printing business.

The free pricing calculator has an electricity section that does this math for you — enter your printer's wattage, the print time and your local rate, and it folds the result into the true cost automatically. If you'd rather understand the whole picture first, start with How to Price 3D Prints: The Complete Guide.

Key takeaways

• kWh = watts × hours ÷ 1000, then cost = kWh × your rate. That's the whole formula.
• Use average draw, not the power-supply rating — real averages are 40–250 W depending on bed size and material.
• The heated bed (size × temperature) drives your power cost more than the hotend.
• Per print it's pennies; per month and per farm it's real money — charge for it as one small explicit line.
• A cheap plug-in energy meter turns your guesses into measured numbers.