A typical hobby FDM print costs between a few cents and a few dollars in materials — but the plastic is only part of the story. A realistic cost covers four factors: filament, electricity, printer depreciation and your own time. This guide walks through each with real numbers, and the free calculator on this site adds them up for you.
The four cost factors
1. Filament
Material cost is grams used × price per gram. A 1 kg spool of standard PLA costs $20–30, so $0.02–0.03 per gram. A 125 g print therefore uses roughly $2.50–3.75 of PLA. Engineering materials (PETG, ABS, nylon) and specialty filaments (carbon-fibre filled, flexible) run higher — see the per-material cost pages for current ranges.
2. Electricity
Most desktop printers draw 50–150 W while printing (heated bed and hotend duty-cycle included). At $0.30 per kWh, a 6-hour print costs about $0.10–0.30. Electricity is rarely the biggest line item, but on long prints and print farms it adds up.
3. Printer depreciation and repairs
Your printer wears out: nozzles, belts, fans, build surfaces. A sensible way to account for it is to spread the printer price over a payback period. A $299 printer paid back over 3 years at 4 printing hours per day works out to roughly $0.07 per print hour — add a repair allowance (10% is a common starting point) on top.
4. Labour
Slicing, bed prep, removal, support cleanup and post-processing take time. Even 15 minutes at a modest $12/hour adds $3.00 — often more than the filament itself. If you sell prints, your time is a real cost; if you price it at zero you are paying to work.
A worked example
A 125 g PLA print that runs for 6 hours: filament $3.25 (from a $25.99 spool), energy $0.27 (150 W at $0.30/kWh), machine wear $0.41 ($299 printer, 3-year payback at 4 h/day) and labour $3.00 (15 minutes at $12/h). True cost: about $6.93 — more than double the "just the plastic" figure most people quote.
Costs people forget
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Failed prints: a 10% failure rate effectively raises every material cost by 10%.
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Supports and rafts: 5–20% extra material on many models.
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Consumables: glue stick, IPA, build sheets, nozzles.
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Drying and storage for hygroscopic filaments (nylon, PETG, TPU).
The easiest way to get all of this right is to let a calculator do the bookkeeping: enter your spool price, wattage, electricity rate and time, and read off an itemised total.
Frequently asked questions
How much does 3D printing cost per hour?
Counting electricity and machine wear only, a desktop FDM printer costs roughly $0.10–0.50 per hour to run. Material and labour come on top and usually dominate.
Is 3D printing cheaper than buying?
For replacement parts, brackets, fixtures and custom-fit items, usually yes — material cost is low and there is no retail margin. For mass-produced commodity items, injection moulding still wins.
How much does a 3D print cost per gram?
With standard PLA at $20–30 per kg, material alone is $0.02–0.03 per gram. A realistic all-in figure (energy, wear, time) is usually 2–4× the raw material number.