3D Printing vs Injection Molding: Where FDM Stops Being Cheaper
The break-even is one division. With published tooling from $1,495 it lands between about 350 and 2,000 units.
A mould is cheaper per part and expensive to start; a printer is the other way round. The crossover is arithmetic: divide the tooling cost by the saving per part. With published tooling prices starting around $1,495 and our own FDM parts at about $5.40 each in the example below, that lands between roughly 440 and 2,300 units — which is why most people asking this question are still better off printing.
Total cost of a run · print vs mould
printed by usmoulded
Printing costs less for the first 439 units.
Our marginal part at volume: $5.40. Tooling ÷ (that − your moulded price) = the crossover.
Tooling quote
Tooling from Protolabs’ published “starting at $1,495”, and the $5k and $10k cases the article works through; the moulded part price is yours to enter. Ours is priced by the checkout’s own module, quantity pricing included, before shipping.
The arithmetic
Moulding has one big fixed cost and a small variable one. Printing has no fixed cost and a larger variable one. So the whole comparison is one division:
The only formula you need
Break-even units = tooling ÷ (printed part − moulded part).
Our sidePast the tenth copy every part is on the deepest rung of the quantity ladder: $5.40 each for the reference part, however many you order.
Our reference part — 60 grams, two hours on the machine — costs $5.48 a unit across a run of a hundred, and every copy past the tenth costs $5.40. Put that against three realistic tooling scenarios:
Tooling figures from published starting prices; moulded per-part costs are illustrative. Our side uses the make cost of a 60 g, 2-hour part.
| Tooling | Moulded part | Saving per part | Break-even |
|---|---|---|---|
| $1,495 (a simple, small mould) | $2.00 | $3.40 | ≈ 440 units |
| $5,000 (a mid-complexity mould) | $1.50 | $3.90 | ≈ 1,282 units |
| $10,000 (multi-cavity or larger) | $1.00 | $4.40 | ≈ 2,273 units |
- $1,495 (a simple, small mould)Moulded part$2.00Saving per part$3.40Break-even≈ 440 units
- $5,000 (a mid-complexity mould)Moulded part$1.50Saving per part$3.90Break-even≈ 1,282 units
- $10,000 (multi-cavity or larger)Moulded part$1.00Saving per part$4.40Break-even≈ 2,273 units
Two of those break-evens sit inside the range Xometry gives for the same question — it puts the crossover “between 250 and 2,000 parts” — and the third lands just past it, so this is not a number we invented to flatter printing.
What the published numbers actually say
Three sources worth reading before you commit to either path, quoted as they stand today:
- Protolabs: moulds "starting at $1,495", tooling "as fast as 7 days", no minimum order quantities, and on-demand moulding described as best at quantities under 2,000.
- Xometry: the break-even "hovers between 250 and 2,000 parts", with a worked example where $10,000 of tooling still wins after 250 units.
- Slant 3D, which runs FDM farms: "injection molds run $10k–$100k+ before part one", and claims additive typically beats moulding up to roughly 250,000 units.
Whoever you ask, the arithmetic is the part to trust: take a real tooling quote and your own per-part price, and do the division — the chart at the top does it for you.
What the break-even leaves out
Time
Tooling is quoted from about a week at the fast end and runs to months for complex moulds made overseas. Printing starts the day the file is right. If your product has a date attached to it, the mould may be the wrong answer whatever the unit price says.
Changes
A mould is a physical object. Changing the part means cutting steel again, or living with the part you have. With printing the file is the tool, so a revision costs a re-upload. If you are still learning what the product should be, that flexibility is usually worth more than the per-part saving.
Inventory
Moulding rewards you for making a lot at once, which means paying for parts before you have sold them and finding somewhere to keep them. Printing lets you order what you need, which is worth real money if demand is uncertain.
What the part is actually like
A moulded part has a smoother surface, no layer lines, and isotropic strength. An FDM part is layered, stronger along the layers than across them, and shows the process if you look. For many products nobody cares. For a premium consumer object held in the hand, some people do.
When to print, and when to cut steel
| Your situation | The usual answer |
|---|---|
| Under a few hundred units | Print. The tooling would not pay for itself. |
| The design is still moving | Print. A mould locks in a part you may not want. |
| Testing whether it sells at all | Print, then decide with real demand data. |
| Thousands of units, design settled for a year | Mould, and run the numbers with a real quote. |
| Between the two, with a deadline | Print the first run while the tooling is cut. |
| Long-tail spares for an older product | Print. A mould for low, steady volume never pays back. |
- Under a few hundred unitsThe usual answerPrint. The tooling would not pay for itself.
- The design is still movingThe usual answerPrint. A mould locks in a part you may not want.
- Testing whether it sells at allThe usual answerPrint, then decide with real demand data.
- Thousands of units, design settled for a yearThe usual answerMould, and run the numbers with a real quote.
- Between the two, with a deadlineThe usual answerPrint the first run while the tooling is cut.
- Long-tail spares for an older productThe usual answerPrint. A mould for low, steady volume never pays back.
What we make, and how fast
FDM is what we do, and here is the shape of it. Parts up to 255 mm on any axis in ten materials on the rack today, including carbon-fibre-filled PETG for stiff functional parts. Priced from your own file in seconds at the quantity you plan to sell, with volume pricing built in: material by the gram, $3.00 per print-hour. Multi-part products can be assembled and hardware fitted for $1 a part. Resin, powder-bed nylon, metal and machining are other processes entirely, and above a few thousand identical parts a mould wins on price.
FAQ
Divide the tooling quote by the per-part saving. With moulds from about $1,495 and an FDM part around $5.40, that is roughly 440 units; with $10,000 tooling it is closer to 2,270. Xometry puts the general crossover between 250 and 2,000 parts. Get a real tooling quote before trusting any published range, including this one.
Protolabs publishes moulds starting at $1,495 for simple parts. Complexity, size and cavity count drive it up quickly; Slant 3D cites $10k–$100k+ for production tooling. The starting price is for a simple, small part, so treat it as a floor rather than an estimate.
For many functional parts, yes, with one caveat: FDM parts are weaker across the layers than along them, so orientation matters. Moulded parts are uniformly strong and smoother. Choose by what the part has to survive, and print a sample before you decide.
Yes, and it is one of the better uses of printing. Ship the first few hundred units while the mould is cut, so the product earns during the weeks tooling takes.
Any number. Price a run from your own file in seconds and pay at checkout; for a large production run, send the quantity and the date you need it by and we schedule it.
Ship the first run while the steel is cut.
Price your part at the quantity you plan to sell, in seconds, with no account. Larger runs are quoted and scheduled.
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