What your 3D printer actually costs in electricity (including standby)

You unplug the printer between prints because it feels wasteful to leave it running, but the display, mainboard, and stepper motors are still drawing power any time it's sitting on standby with a job queued — and that trickle runs 16, 20, sometimes close to 24 hours a day, every day of the month. Meanwhile the actual printing — the part you were budgeting for — might only be running a fraction of that time. Most people price their 3D printing electricity by multiplying the printer's running wattage by the hours of active printing and stop there, which misses a real chunk of the bill.

Printing time is not the whole story

Monthly electricity cost from a printer breaks into three buckets, and only one of them is what most people think of as "printing":

• Active printing — the wattage while the machine is actually laying down material, running the print head, heated bed, and motors.
• Idle/standby — the wattage the printer draws whenever it's powered on but not printing: mainboard, screen, steppers holding position, sometimes a partially-heated bed waiting on the next job.
• Cure time (resin only) — a separate UV curing station running after each print to harden the part.

The math for the total is simple once you separate the buckets: convert each wattage to kilowatts, multiply by hours, multiply by how often it happens in a month, and add electricity rate at the end. The part people skip is the idle bucket, because standby wattage per hour looks trivial — until you multiply it by how many hours a month the printer actually sits idle rather than off.

FDM vs. resin: different power profiles

The two common printer types don't cost the same way to run:

• FDM printers spend most of their power on the heated bed and hotend, commonly running somewhere around 100–150W while printing. There's no separate curing step — the part is done when the print finishes.
• Resin printers draw noticeably less while printing — often in the 50–70W range, since there's no heated bed to speak of — but every print needs a separate post-cure step in a UV curing station, commonly drawing somewhere around 30–50W for 10–20 minutes per part. That cure time is a real, separate line item that an FDM cost estimate simply doesn't have.

Because resin's per-print running wattage is lower, a straight watts-times-hours comparison can make resin printing look cheaper overall than FDM — and for the printing step itself, it usually is. The cure station adds a modest amount back, but the more consequential difference for either machine, in practice, tends to be the standby time neither number accounts for.

Worked example: a busy FDM printer

Take an FDM printer running at 120W, doing 8-hour prints, 20 prints a month, with 5W of idle draw for 16 hours a day between jobs, at $0.16/kWh:

• Printing energy: (120W ÷ 1000) × 8 hours × 20 prints = 19.2 kWh/month.
• Idle energy: (5W ÷ 1000) × 16 hours × 30 days = 2.4 kWh/month.
• Total: 21.6 kWh/month → 21.6 × $0.16 = $3.46/month, or about $41.47/year.
• Cost per print: (120W ÷ 1000) × 8 hours × $0.16 ≈ $0.154 each.

Here idle draw is a modest 11% of the bill — not dominant, but not nothing over a year. The real trap shows up on printers with a higher standby draw. Bump idle consumption to a more typical 12W — closer to reality for boards that keep steppers energized or a display permanently lit — and leaving the printer powered around the clock instead of 16 hours a day adds roughly 8.6 kWh/month on its own, pushing the total bill up by close to a third versus the same printing workload with the machine properly powered down between jobs.

Worked example: the same workload in resin

Same 20 prints a month, same 16 hours/day idle at 5W, but now on a resin printer at 60W running watts with a 40W cure station running 15 minutes (0.25 hours) per print:

• Printing energy: (60W ÷ 1000) × 8 hours × 20 prints = 9.6 kWh/month.
• Cure energy: (40W ÷ 1000) × 0.25 hours × 20 prints = 0.2 kWh/month.
• Idle energy: 2.4 kWh/month (unchanged).
• Total: 12.2 kWh/month → 12.2 × $0.16 = $1.95/month, or about $23.42/year.

Roughly half the FDM printer's bill for the same print count — mostly because resin doesn't run a heated bed. The cure station's contribution is small on its own, but it's a cost an FDM comparison simply doesn't have, and it's worth including if you're deciding between the two processes on running cost as well as material cost.

Cutting the idle cost without babysitting the printer

A few practical habits shrink the standby line without adding much friction:

• Put the printer on a smart plug that powers down after a print finishes, rather than relying on the machine's own low-power sleep mode.
• Batch print files so the machine spends more of its powered-on hours actually printing and less time sitting idle waiting for the next job to be queued.
• Check your specific board's standby draw rather than assuming — some control boards and touchscreens pull noticeably more idle power than others, and it's the one number in this whole calculation that's genuinely printer-specific.

Our 3D printer electricity cost calculator takes your printer type, running wattage, hours and count of prints, idle wattage and hours, and (for resin) cure station wattage and time, and returns your cost per print alongside full monthly and annual totals — split out by printing, idle, and cure so you can see exactly where the money is going, not just what a single print appears to cost.