What matters
- Treat tooling as a project cost and molded parts as a recurring cost.
- Part geometry, tool architecture, resin, cycle time, and quality requirements move the estimate more than part size alone.
- Compare quotes on the same annual volume, tool life, cavity count, resin basis, Incoterm, and inspection scope.
Start with two numbers, not one
An injection molding budget has two different behaviors. The mold is paid for before production and changes when the design changes. Part cost repeats with every shot. Combining them into a single headline number hides the decision you actually need to make.
For an early comparison, keep tooling, qualification, production, packaging, freight, and tax on separate lines. This makes a low-volume bridge tool comparable with a production mold even when their up-front prices are far apart.
| Cost bucket | Usually driven by | Paid |
|---|---|---|
| Tooling | Part geometry, steel, cavities, actions, hot runner | Up front |
| Qualification | Sampling rounds, measurement, material trials | Before approval |
| Part production | Resin, cycle time, machine rate, labor, scrap | Per run |
| Logistics | Pack-out, shipment size, destination, Incoterm | Per shipment |
What changes the mold price
A compact part can still need an expensive tool. A side hole may require a slide; a cosmetic face may need careful gate placement and polishing; a flat assembly surface may need better cooling and tighter process control.
- External undercuts, internal threads, collapsible cores, unscrewing mechanisms, and lifters.
- Large projected area, deep ribs, difficult venting, or long flow lengths.
- Multiple cavities, family tooling, hot runners, valve gates, or insert loading.
- Tool-life target, mold steel, corrosion resistance, texture, and changeable inserts.
- Inspection reports, material traceability, validation protocol, and spare components.
A worked planning model
Suppose the tool is $18,000, qualification is $2,000, and the quoted molded part is $0.84 before freight. At 25,000 parts, the simple program cost is $41,000, or $1.64 per part after spreading the up-front cost across that run.
That is a planning calculation, not a supplier quote. It changes if the tool is reused for a later run, if resin is indexed separately, or if packaging and freight sit outside the unit price.
What to send for a quote that can be compared
If one of these is unknown, label it as an assumption. A transparent assumption is easier to correct than a quote built around a silent guess.
- A STEP file plus a controlled 2D drawing for critical dimensions and notes.
- Resin grade, color, additives, texture, and appearance surfaces.
- First-order quantity, annual demand, expected program life, and ramp schedule.
- Tool ownership, preferred mold location, export requirements, and target molding location.
- Inspection level, capability requirements, certifications, packaging, and delivery destination.
Use this as a design review, not a production release
These guides support early planning. The selected resin supplier, toolmaker, and molder still need to confirm the final geometry, process window, tolerances, safety factors, validation plan, and commercial assumptions for your application.