How do you calculate mold cost per part?

Multiply parts by cost per cavity-shot and by tool-life realization, add the maintenance reserve, then divide by parts. With 250,000 parts at $0.18, 85% realization and a $6,000 reserve, total mold cost is $44,250 and per-part cost is $0.177.

Why apply a tool-life realization factor?

Molds seldom reach their theoretical life — damage, program cancellation, or design changes cut it short. The 85% factor discounts the variable cost to reflect the life you actually get, here reducing $45,000 of variable cost to $38,250.

What is a good mold cost per part?

It depends on part size and volume, but for high-volume commodity parts, tooling burden under $0.20/part is common. The $0.177/part default is reasonable for a 250,000-part run on a mid-cost tool.

What does the maintenance reserve cover?

It sets aside money for wear items — hot-runner tips, ejector pins, slides, and periodic polishing. The $6,000 reserve is the fixed adder that lands entirely in total mold cost regardless of shot count.

How does volume change mold cost per part?

The $6,000 fixed reserve spreads thinner as volume rises, so per-part cost falls with higher quantities. At 250,000 parts the reserve adds $0.024/part; doubling the volume roughly halves that fixed share.

Variable vs fixed mold cost — what's the split?

Variable cost is the per-shot tooling cost scaled by realization ($38,250 here); fixed cost is the maintenance reserve ($6,000). Knowing the split shows how sensitive your per-part number is to volume.

Tooling, Fixtures, Dies & Mold Economics calculator

Mold Cost Per Part Calculator

Mold cost per part converts a mold's build and upkeep cost into the tooling cost carried by each molded piece, so quotes and margins reflect the real tool burden. Injection molders, estimators, and buyers use it to compare tools, set piece prices, and decide when a mold has paid off. Because a mold rarely delivers its full rated life, the calculation discounts by a realization factor and adds a maintenance reserve for the wear items that keep it running. The result is a defensible per-part number rather than a best-case one.

What this calculator does

Estimate amortized mold cost per part from projected volume, per-part tool allocation, realized tool life, and maintenance reserve.
a tooling estimator needs to spread injection mold cost across projected part volume for a quote.
It computes the amortized mold cost per part by combining variable per-shot cost, tool-life realization, and a fixed maintenance reserve, then dividing by parts produced.

Formula used

Total mold cost over life = molded parts × mold cost per part × tool life realization + mold maintenance reserve
Amortized mold cost per part = total mold cost over life ÷ molded parts

Inputs explained

Molded parts over tool life:
Mold cost per cavity-shot:
Usable share of rated tool life:
Mold maintenance reserve:

How to use the result

Use it when quoting a molded part, comparing candidate molds, or checking when a mold has recovered its cost.
It treats the maintenance reserve as a single fixed lump; molds with heavy hot-runner or slide maintenance may need reserves that scale with shot count.

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 14,378 furniture and related products establishments employing about 355,594 workers (Census County Business Patterns, 2023).

Common questions

How do you calculate mold cost per part? Multiply parts by cost per cavity-shot and by tool-life realization, add the maintenance reserve, then divide by parts. With 250,000 parts at $0.18, 85% realization and a $6,000 reserve, total mold cost is $44,250 and per-part cost is $0.177.
Why apply a tool-life realization factor? Molds seldom reach their theoretical life — damage, program cancellation, or design changes cut it short. The 85% factor discounts the variable cost to reflect the life you actually get, here reducing $45,000 of variable cost to $38,250.
What is a good mold cost per part? It depends on part size and volume, but for high-volume commodity parts, tooling burden under $0.20/part is common. The $0.177/part default is reasonable for a 250,000-part run on a mid-cost tool.
What does the maintenance reserve cover? It sets aside money for wear items — hot-runner tips, ejector pins, slides, and periodic polishing. The $6,000 reserve is the fixed adder that lands entirely in total mold cost regardless of shot count.
How does volume change mold cost per part? The $6,000 fixed reserve spreads thinner as volume rises, so per-part cost falls with higher quantities. At 250,000 parts the reserve adds $0.024/part; doubling the volume roughly halves that fixed share.

Last reviewed 2026-05-12.