Why divide the fixture by good parts instead of all parts?

Scrapped parts never ship, so they cannot pay the fixture back. Dividing by the good parts that remain puts the full investment on the output that actually sells.

Does a higher scrap rate raise the fixture cost per part?

Yes. The investment is fixed, and scrap reduces the good parts carrying it, so each remaining part pays more. At a 10% scrap rate a 6,000-part life leaves 5,400 paying parts.

What expected production should I enter?

The good parts the fixture will run before it is rebuilt or retired, across every order for that part. Do not enter one batch unless that batch is the fixture's whole life.

When does a fixture become too expensive?

When the cost it adds per part exceeds the target you set. Lower the investment, run more parts, or share the fixture across several part numbers to bring the per-part cost down.

CNC Machining calculator

Fixture Amortization Calculator

Spread a fixture or workholding investment across the good parts it will produce. Enter the investment, the expected production over its life, and the scrap rate that reduces the paying parts.

What this calculator does

Fixture cost per good part from the investment, the expected production over its life, and the scrap rate.

Formula used

Effective good parts = expected production × (1 − scrap rate ÷ 100)
Fixture cost per part = fixture or workholding investment ÷ effective good parts
Base fixture cost per part = fixture or workholding investment ÷ expected production
Scrap adder per part = fixture cost per part − base fixture cost per part
Gap to target = fixture cost per part − target fixture cost per part

Inputs explained

Fixture or Workholding Investment: Total spent on the fixture or workholding.
Expected Production Over Life: Good parts the fixture is expected to run over its life.
Scrap Rate: Share of parts scrapped before the fixture life ends.
Target Fixture Cost per Part: Per-part fixture cost the job should beat.

How to use the result

Best suited to justifying a fixture purchase, costing a repeat order, testing a higher scrap rate.
Fixture maintenance, storage, and engineering changes are excluded. A product cancelled mid-life strands part of the investment.

Current U.S. benchmarks

The producer price index for steel mill products stands at 381.162 (BLS, Aug 2026), up 23.4% from a year earlier. Quotes priced off last quarter's material cost miss this move.
The U.S. has 17,154 machine shops establishments employing about 223,303 workers (Census County Business Patterns, 2023).

Common questions

Why divide the fixture by good parts instead of all parts? Scrapped parts never ship, so they cannot pay the fixture back. Dividing by the good parts that remain puts the full investment on the output that actually sells.
Does a higher scrap rate raise the fixture cost per part? Yes. The investment is fixed, and scrap reduces the good parts carrying it, so each remaining part pays more. At a 10% scrap rate a 6,000-part life leaves 5,400 paying parts.
What expected production should I enter? The good parts the fixture will run before it is rebuilt or retired, across every order for that part. Do not enter one batch unless that batch is the fixture's whole life.
When does a fixture become too expensive? When the cost it adds per part exceeds the target you set. Lower the investment, run more parts, or share the fixture across several part numbers to bring the per-part cost down.

Last reviewed 2026-10-01.