How do you calculate rework cost?

Multiply units built by per-unit rework cost by the defect rate, then add fixed setup. Here 30,000 x $9.75 x 4% = $11,700 variable, plus $3,500 setup, for $15,200 total.

What is the rework cost per unit?

Amortize total rework cost across every unit built, not just the defective ones. The $15,200 total over 30,000 units is about $0.51 per unit, a figure you can fold into your loaded cost.

Is rework cost the same as scrap cost?

No. Rework repairs a unit so it ships; scrap discards it and loses the full BOM and labor already invested. This tool models rework only, so units that fail rework and become scrap must be costed separately.

What is a good defect rework rate for IoT hardware?

Mature SMT and box-build lines often run rework rates in the low single digits; 4% is workable but worth attacking. Dropping it to 2% would roughly halve the $11,700 variable cost in the example.

Why include a fixed setup cost?

Standing up a rework cell (fixtures, a reflow or hot-air station, a dedicated tester) costs money before the first unit is touched. At $3,500 spread over 30,000 units it adds about $0.12 per unit that pure per-defect math would miss.

How do I lower rework cost per unit?

Reduce the defect rate through process or supplier fixes, or spread the fixed setup over a larger run. The variable term scales with defect rate, so prevention at the source usually beats getting faster at repair.

Smart Home & Consumer IoT Hardware calculator

Rework Cost Calculator

Rework Cost totals what it costs to fix defective smart home or IoT units during a production run, combining the per-unit labor-and-parts to repair each defect, the share of the run that needs rework, and any one-time cost to stand up the rework station. Quality and operations managers use it to put a real dollar figure on scrap-and-rework so it can be attacked, quoted, or traded against a prevention investment. On a consumer IoT line, a 4% rework rate on a 30,000-unit run is not a rounding error; reflow touch-ups, connector reseats and re-test time add up fast. This calculator amortizes both the variable repair cost and the fixed setup across the run so you see the true cost per unit.

What this calculator does

Estimates the cost of reworking defective smart home devices, covering rework labor, replacement parts, and station setup.
A manufacturing engineer quantifies expected rework cost on a connected-device build to weigh it against scrap or tighter process control.
It computes total rework cost from run size, per-unit rework cost, defect rate and fixed setup, and amortizes it to a per-unit figure.

Formula used

Rework Cost = Units Built x Rework Labor+Parts x Defect Rework Rate% + Line Setup
Per-unit rework cost = Rework Cost / Units Built (amortized across the run)

Inputs explained

Units built in the production run:
Rework labor + parts per defective unit:
Defect rework rate (units needing rework):
One-time line setup for rework:

How to use the result

Use it when estimating quality cost for a run, quoting a program, or building the business case for a defect-prevention fix.
It assumes a single blended rework cost per unit and a flat defect rate; multi-failure-mode runs or units that fail rework and become scrap need a more detailed cost-of-quality model.

Current U.S. benchmarks

Global copper trades at $13,484 per tonne (IMF via FRED, May 2026), up 41.5% in a year, and U.S. industrial electricity averages 8.66 cents per kWh. Both feed electrified-hardware unit economics.
Steel mill PPI stands at 348.53 (BLS, May 2026), up 6.7% from a year earlier. New factory orders are up 2.3% year over year (Census).

Common questions

How do you calculate rework cost? Multiply units built by per-unit rework cost by the defect rate, then add fixed setup. Here 30,000 x $9.75 x 4% = $11,700 variable, plus $3,500 setup, for $15,200 total.
What is the rework cost per unit? Amortize total rework cost across every unit built, not just the defective ones. The $15,200 total over 30,000 units is about $0.51 per unit, a figure you can fold into your loaded cost.
Is rework cost the same as scrap cost? No. Rework repairs a unit so it ships; scrap discards it and loses the full BOM and labor already invested. This tool models rework only, so units that fail rework and become scrap must be costed separately.
What is a good defect rework rate for IoT hardware? Mature SMT and box-build lines often run rework rates in the low single digits; 4% is workable but worth attacking. Dropping it to 2% would roughly halve the $11,700 variable cost in the example.
Why include a fixed setup cost? Standing up a rework cell (fixtures, a reflow or hot-air station, a dedicated tester) costs money before the first unit is touched. At $3,500 spread over 30,000 units it adds about $0.12 per unit that pure per-defect math would miss.

Last reviewed 2026-05-12.