How this instrument works
Buy-vs-outsource for a 3D printer is the question a maker, an Etsy seller, a prop builder, or an engineer prototyping a bracket runs before laying out a few hundred dollars for a machine instead of paying a print bureau — Shapeways, Craftcloud, JLCPCB, or a local makerspace — for each part as it's needed. Unlike a company sizing up a big capital purchase in dollars and years, the natural unit here is prints: how many of this part, or parts like it, will actually get made. That's the number the break-even answer is expressed in, not a dollar figure or a payback period.
The arithmetic is a straight race between two lines. Buying totals a fixed printer cost plus material cost times the number of prints; outsourcing totals a per-print rate times that same number, with nothing fixed at all. Because outsourcing has no upfront cost, it starts cheaper — but it climbs faster, since every unit costs the full outsource rate instead of just material. The crossing point, break-even number of prints, is the printer cost divided by the gap between the outsource rate and the material cost: the bigger that per-print gap, the fewer prints it takes to earn the machine back. On the numbers used here — a $500 printer, $2 of material, and a $15 outsource quote — that gap is $13, and the printer pays for itself in well under forty prints.
What the sheet cannot see matters as much as what it computes. A failed print still burns filament or resin, so the real material cost per successful part usually runs higher than a spool-price estimate; nozzle wear, bed releveling, and the odd repair aren't in the formula either, and neither is electricity or the hours spent tuning a profile and cleaning up supports. Outsourced cost per print, $ is itself an average — a bureau prices by material volume, wall thickness, and finish, so a part larger or fussier than the one you priced will cost more to send out than this sheet assumes.
- Enter 3D printer cost, $ for the machine itself — the price tag, before any filament or resin.
- Enter Material cost per print, $ for what one successful part actually consumes in filament or resin.
- Enter Outsourced cost per print, $ for what a print bureau or service would charge for that same part, delivered.
- Set Prints planned to how many you genuinely expect to make, then compare Total cost if you buy the printer against Total cost if you outsource.
- Check Break-even number of prints: plan fewer and outsourcing costs less; plan more and the printer earns its price back.
Worked example — a $500 printer against a $15 quote
Take the default sheet: a $500 printer, $2 of material per part, a $15 outsource quote, and 50 prints planned. Total cost if you buy the printer comes to 500 + 2 × 50 = $600. Total cost if you outsource comes to 15 × 50 = $750 — outsourcing costs $150 more at this volume, because every one of the 50 parts carries the full $15 rate instead of just the $2 of material.
Break-even number of prints is 500 ⁄ (15 − 2) = 38.4615… — just over 38 prints. Since 50 prints clears that threshold, buying wins on these numbers; drop the plan to, say, 20 prints instead and outsourcing would come out ahead, because the printer's fixed cost wouldn't yet be spread over enough parts to beat the per-print rate. The break-even count itself doesn't move with volume — only the two totals it's compared against do.
Questions
What counts as material cost per print?
The filament or resin one successful part actually consumes, priced from what the spool or bottle cost you — not the manufacturer's per-gram list price, which rarely matches real usage once purge, rafts, and supports are included. Because failed prints still burn material without producing a usable part, a shop that fails one print in ten should push this figure higher than a clean per-part estimate would suggest, or the break-even count will read more favorably than it turns out to be.
Why does the break-even number stay the same as I change how many prints I plan?
Because it's set entirely by the printer cost and the gap between the outsource rate and the material cost — Prints planned never enters that formula. Raising the planned print count doesn't move Break-even number of prints; it only moves how far Total cost if you buy the printer and Total cost if you outsource have separated by the time you get there, which is why the two totals, not the break-even figure, are what actually respond to a bigger order.
Does Outsourced cost per print, $ assume every part is the same size?
Yes — the sheet treats it as one flat rate, which is a simplification worth checking before trusting the answer. Print bureaus quote by material volume, wall thickness, and surface finish, so a small bracket and a large enclosure from the same shop rarely cost the same to outsource. Price the actual part or parts you plan to make, not a rough average, and rerun the sheet if your project mixes small and large prints.
What does this calculation leave out?
Failed prints and the material they waste, printer maintenance such as nozzles, belts, and bed releveling, electricity, and the hours spent slicing, tuning, and cleaning up supports. It also skips the time value of owning the machine — a same-day reprint versus a shipping wait — and any resale value left in the printer if you stop using it. All of those sit outside the three inputs this sheet adds together.
Should I buy a printer once I pass the break-even number of prints?
The sheet only reports where the two totals cross, not what to do about it — that crossing point means Total cost if you buy the printer and Total cost if you outsource are equal, nothing more. Planned volume above that number means owning costs less on this arithmetic alone; the maintenance, skill, and time this sheet excludes belong in the decision too, and only you can weigh those against a smaller printed dollar gap.
Does a cheaper printer always lower the break-even point?
Yes, mechanically — printer cost sits in the numerator, so a cheaper machine needs fewer prints to close the gap with outsourcing. But budget printers often fail more often and need more manual tuning, and both of those raise the real material cost per successful part beyond what a spool-price estimate captures, which quietly pushes the true break-even count higher than the sheet's clean division shows.
References
- IRS — Publication 946, How To Depreciate Property
- U.S. Small Business Administration — calculate your startup costs
Read this first: This instrument shows arithmetic, not advice. Real offers add fees, taxes and terms that vary by lender and place — verify the figures against your actual paperwork before deciding anything.