How do you calculate test failure cost?

Multiply units tested by the expected failure rate to get expected failures, price them at the cost per failed unit, then add the fixed test setup. Here 100 units x 5% = 5 failures x $45 = $225, plus $250 fixed, for a $475 total.

What is the per-unit test failure cost?

Divide total cost by units tested. In this example $475 across 100 units is $4.75 per unit tested, a handy number for quoting quality cost into unit price.

What does the capture rate represent?

It is the share of the batch you expect to fail final test, 5% in the example. Feed it from recent first-pass yield; a rising failure rate multiplies straight into this cost.

Why include a fixed cost?

Test fixtures, hipot stations, and calibration carry cost regardless of volume. The $250 fixed term spreads that overhead into the total, which is why per-unit cost falls as batch size rises.

Is 100% testing worth it for transformers?

Compare the per-unit test failure cost against the field-return cost of an escaped defect. When escapes are expensive, as with safety-critical hipot failures, the $38.50/piece here is often easily justified.

How can I lower test failure cost?

Attack the failure rate upstream rather than the test itself. Reducing incoming winding and lamination defects lowers the units-times-rate term far more than trimming fixed test cost.

Transformers, Coils & Magnetics Manufacturing calculator

Test Failure Cost Calculator

Test failure cost quantifies what final electrical testing of transformers and coils really costs when you account for how many units fail, the rework or scrap cost each carries, how effectively the test catches defects, and the fixed cost of the test setup. Quality and cost engineers in magnetics manufacturing use it to decide whether tighter hipot, turns-ratio, or surge testing pays for itself. Rolling the per-unit figure alongside the total makes it easy to compare test strategies across product lines. It turns an abstract quality gate into a dollar figure a plant manager can act on.

What this calculator does

Test failure cost quantifies what final electrical testing of transformers and coils really costs when you account for how many units fail, the rework or scrap cost each carries, how effectively the test catches defects, and the fixed cost of the test setup.
Use it when test failure cost in transformers, coils and magnetics manufacturing is being put through a transformers, coils and magnetics manufacturing weighted-cost review.
It multiplies tested quantity by cost per failed unit and the capture rate, adds the fixed test cost, and also divides the total by quantity for a per-unit figure.

Formula used

Expected failure cost = units tested × failure rate % × cost per failed unit + fixed test setup
Expected failures = units tested × failure rate %

Inputs explained

Units tested in batch:
Cost per failed unit:
Expected test failure rate:
Fixed test setup cost:

How to use the result

Use it when justifying a test-equipment upgrade, pricing quality into a transformer quote, or comparing 100% testing against sampling.
It models the capture rate as a flat multiplier on cost and does not separately value escaped defects that reach the field, which usually cost far more than in-house catches.

Current U.S. benchmarks

The producer price index for copper and brass mill shapes stands at 542.853 (BLS, Jul 2026), up 52.8% from a year earlier. Quotes priced off last quarter's material cost miss this move. Global copper trades at $13,543 per tonne (IMF via FRED, Jul 2026).
The U.S. has 5,397 electrical equipment and appliances establishments employing about 369,437 workers (Census County Business Patterns, 2023).

Common questions

How do you calculate test failure cost? Multiply units tested by the expected failure rate to get expected failures, price them at the cost per failed unit, then add the fixed test setup. Here 100 units x 5% = 5 failures x $45 = $225, plus $250 fixed, for a $475 total.
What is the per-unit test failure cost? Divide total cost by units tested. In this example $475 across 100 units is $4.75 per unit tested, a handy number for quoting quality cost into unit price.
What does the capture rate represent? It is the share of the batch you expect to fail final test, 5% in the example. Feed it from recent first-pass yield; a rising failure rate multiplies straight into this cost.
Why include a fixed cost? Test fixtures, hipot stations, and calibration carry cost regardless of volume. The $250 fixed term spreads that overhead into the total, which is why per-unit cost falls as batch size rises.
Is 100% testing worth it for transformers? Compare the per-unit test failure cost against the field-return cost of an escaped defect. When escapes are expensive, as with safety-critical hipot failures, the $38.50/piece here is often easily justified.

Last reviewed 2026-08-11.