How this instrument works
A 3D print's sticker price is almost never just the filament. Four separate costs stack up on every job: material (the filament actually consumed, priced per kilogram), electricity (the printer's power draw over the whole print duration), machine time (a per-hour rate that recovers the printer's own purchase price and wear over its working life), and any post-processing (support removal, sanding, painting) done by hand afterward. Add those four together and you have the print's raw cost before accounting for risk.
That last piece — risk — is what the failure-rate markup covers. Filament jams, warped beds, and stringing ruin a real share of hobbyist and small-batch prints, and the cost of those failures has to be recovered somewhere, usually by adding a percentage on top of every successful print's price. A 5% markup means, on average, one print in twenty needs to fail completely before you're still breaking even across the batch.
This instrument totals all four cost components, applies your chosen failure-rate percentage, and shows the total alongside each component so you can see which one is actually driving the price — often electricity is a rounding error next to machine-time depreciation on a slow, expensive-to-run printer, while on a fast, cheap-to-run one filament dominates instead.
- Enter Filament used in grams and Filament price per kg — these multiply directly into material cost.
- Enter Print time in hours and Printer power draw in watts to compute the electricity cost at your local rate.
- Enter Electricity rate in $/kWh and a Machine time / depreciation rate in $/hour to recover printer wear and ownership cost.
- Add any Post-processing cost for hand-finishing work done after the print completes.
- Set a Failure-rate markup percentage to build in the average cost of prints that don't succeed.
- Read Total print cost, along with the Material, Electricity and Machine cost breakdown above it.
Worked example — a 50g, 4-hour hobbyist print
Print 50g of $20/kg PLA on a 150W printer for 4 hours, paying $0.15/kWh for electricity and charging $2/hour for machine time, with no post-processing and a 5% failure markup. Material cost is (50/1000) x 20 = $1.00. Electricity cost is (150/1000) x 4 x 0.15 = $0.09. Machine cost is 4 x 2 = $8.00. Those three sum to $9.09, and applying the 5% failure markup brings the total to $9.09 x 1.05 = $9.5445, which the instrument rounds to $9.54.
Notice that machine time, not filament, is the dominant cost here — at $8.00 it's eight times the material cost, which is typical for small, fast-printing hobbyist jobs where the printer's own depreciation rate matters more than the plastic it consumes.
Questions
Why is machine time included as a cost — isn't the printer already paid for?
The printer was paid for once, but every hour it runs wears down the nozzle, belts, bearings and bed, and eventually needs replacement or repair. A machine-time rate spreads that eventual replacement cost, plus any loan or opportunity cost tied up in owning the printer, across every hour of use — the same depreciation logic used for any piece of production equipment. If you're printing purely for yourself with no interest in recovering hardware costs, you can set this rate to $0 and see only material and electricity.
How do I estimate my printer's actual power draw in watts?
Check the printer's power supply rating (often printed on the PSU itself, e.g. "24V 15A" implies a 360W maximum), or use a plug-in power meter for an exact reading during a real print — actual draw is usually well under the PSU's maximum rating, since the hot end and bed only pull full power intermittently. A typical desktop FDM printer draws 100-250W in steady operation; larger heated-bed printers or those printing high-temperature materials like ABS draw more.
What failure-rate percentage should I actually use?
It depends entirely on your printer's reliability and how demanding the print is — a well-tuned printer running simple geometry might fail under 2% of the time, while a printer running long, complex, or unsupervised overnight prints can fail 10-20% of the time. Track your own failure rate over 20-30 prints (failures divided by total attempts) and use that percentage here rather than guessing, since it directly scales your total cost.
Does this include the cost of supports and rafts that get thrown away?
Yes, indirectly — any filament used for supports, rafts, or brims is part of the total grams you weigh or estimate for Filament used, since your slicer's material-usage estimate already includes that waste material. Enter the slicer's full filament-weight estimate for the print, not just the weight of the finished part after supports are removed.
Why would I add a post-processing cost if I'm not selling the print?
You can leave it at $0 if you're only tracking material and machine cost for personal use. It exists for anyone pricing prints for sale or for a paid commission, where sanding, gluing multi-part prints together, painting, or removing supports by hand takes real time that should be valued alongside the print itself, not treated as free labor.