How do you calculate molded part cost?

Add material cost per part, conversion (machine) cost per part, and amortized tooling per part. With $0.095 material, $0.042 conversion, and $0.017 tooling, the manufacturing cost is $0.154 per part.

How is amortized tooling cost per part found?

Divide the total tool cost by the program volume it will produce. A $34,000 mold spread over 2 million parts adds $0.017 per part, matching the default in this example.

What is a good material-to-conversion ratio?

There is no single target, but the ratio tells you where to focus. In the example, material is $0.095 of $0.154 (about 62%), so resin selection and regrind strategy move the cost more than shaving cycle time.

Does this part cost include profit margin?

No. This is manufacturing cost. You add margin, secondary operations (printing, assembly), packaging, and freight on top to reach the quoted selling price.

How do I lower conversion cost per part?

Cut cycle time, raise cavitation, or move to a lower hourly press. Since conversion is the machine hour rate times cycle time divided by cavities, any of those three levers reduces the $0.042 conversion figure.

Why amortize tooling into the part cost instead of charging it upfront?

Many programs roll tooling into piece price so the customer pays as parts ship. Amortizing it shows the true loaded cost per part and protects you if the program ends before the tool is paid off.

Injection Molding calculator

Molded Part Cost Calculator

Molded part cost is the sum of the three core cost buckets in injection molding: the resin in the part, the press time to convert it, and the share of tooling spread across the program volume. Estimators and buyers use it as the manufacturing cost floor before margin, secondary operations, packaging, and freight are added to reach a selling price. Knowing the breakdown matters because the cheapest lever to pull differs by part: a thick, high-resin part is dominated by material, while a fast-cycling commodity part is dominated by conversion. This calculator gives you the clean per-part manufacturing cost so you can see where the money actually goes.

What this calculator does

Calculate total molded part cost by combining material cost, machine conversion cost, and amortized tooling per part.
Use this for part pricing, customer quotations, make-vs-buy decisions, or comparing cost impact of design changes (wall thickness, material grade, cavitation).
It adds material cost per part, machine conversion cost per part, and amortized tooling cost per part into a single manufacturing cost per part.

Formula used

Total part cost = Material + Conversion + Tooling (per part)
Add margin, secondary operations, packaging, and shipping for selling price

Inputs explained

Material cost per part:
Machine/conversion cost per part:
Amortized tooling cost per part:

How to use the result

Use it when quoting a new program or auditing an existing part to see which cost bucket dominates before adding margin.
It is a manufacturing cost only; it excludes margin, secondary operations, packaging, and freight, so it is not a selling price.

Current U.S. benchmarks

The producer price index for plastic resins and materials stands at 319.371 (BLS, May 2026), up 19.5% from a year earlier. Quotes priced off last quarter's material cost miss this move.
The U.S. has 9,635 plastics product manufacturing establishments employing about 677,302 workers (Census County Business Patterns, 2023).

Common questions

How do you calculate molded part cost? Add material cost per part, conversion (machine) cost per part, and amortized tooling per part. With $0.095 material, $0.042 conversion, and $0.017 tooling, the manufacturing cost is $0.154 per part.
How is amortized tooling cost per part found? Divide the total tool cost by the program volume it will produce. A $34,000 mold spread over 2 million parts adds $0.017 per part, matching the default in this example.
What is a good material-to-conversion ratio? There is no single target, but the ratio tells you where to focus. In the example, material is $0.095 of $0.154 (about 62%), so resin selection and regrind strategy move the cost more than shaving cycle time.
Does this part cost include profit margin? No. This is manufacturing cost. You add margin, secondary operations (printing, assembly), packaging, and freight on top to reach the quoted selling price.
How do I lower conversion cost per part? Cut cycle time, raise cavitation, or move to a lower hourly press. Since conversion is the machine hour rate times cycle time divided by cavities, any of those three levers reduces the $0.042 conversion figure.

Last reviewed 2026-05-12.