Calculator Inputs
Use the fields below to estimate the full financial impact of corrective work, retesting, delays, and recovery credits.
Example Data Table
| Metric | Example Value |
|---|---|
| Lot Size | 1,200 units |
| Defective Units | 84 units |
| Rework Hours per Unit | 1.75 hours |
| Labor Rate per Hour | $22.00 |
| Material Cost per Unit | $6.50 |
| Overhead Rate per Hour | $9.00 |
| Inspection Cost per Unit | $3.50 |
| Downtime | 4 hours at $75.00 |
| External + Shipping + Admin | $180 + $90 + $50 |
| Recovery Credit | $120.00 |
| Contingency | 8% |
| Total Rework Cost | $6,368.76 |
| Cost per Defective Unit | $75.82 |
Formula Used
1) Total Rework Hours
Total Rework Hours = Defective Units × Rework Hours per Unit
2) Gross Rework Cost
Gross Rework Cost = Labor + Materials + Overhead + Inspection + Downtime + External Services + Expedited Shipping + Admin
3) Net Before Contingency
Net Before Contingency = Gross Rework Cost − Recovery Credit
4) Contingency Cost
Contingency Cost = Net Before Contingency × (Contingency Percent ÷ 100)
5) Final Total Rework Cost
Total Rework Cost = Net Before Contingency + Contingency Cost
6) Unit Impact
Cost per Defective Unit = Total Rework Cost ÷ Defective Units
Cost per Produced Unit = Total Rework Cost ÷ Lot Size
7) Rework Share of Lot Value
Rework % of Lot Value = (Total Rework Cost ÷ (Lot Size × Original Unit Value)) × 100
How to Use This Calculator
- Enter your currency symbol so reports match local costing format.
- Add the total lot size and the number of defective units.
- Enter corrective labor time, labor rate, material cost, and overhead rate.
- Include retest cost, downtime, outside repair charges, rush freight, and admin time.
- Enter any recovery credit from salvage, claims, or supplier reimbursement.
- Add a contingency percentage for hidden or still-emerging corrective costs.
- Enter original unit value if you want rework cost compared with lot value.
- Press Calculate Rework Cost to show results above the form and export them as CSV or PDF.
FAQs
1. What does this calculator measure?
It estimates the full financial burden of rework in quality control, including labor, materials, retesting, downtime, overhead, admin effort, and recoveries.
2. Why include downtime cost?
Downtime captures lost productive capacity. Without it, rework often appears cheaper than it really is, especially on constrained lines or bottleneck operations.
3. What is recovery credit?
Recovery credit represents offsets such as salvage value, supplier chargebacks, warranty recoveries, or reusable material that lowers net rework cost.
4. Should overhead be based on hours or units?
This model applies overhead by rework hour. That works well when supervision, machine support, utilities, and handling effort rise with corrective time.
5. When should I use contingency percent?
Use contingency when some corrective expenses are uncertain, such as extra inspections, hidden failures, additional documentation, or delayed customer shipments.
6. Can this tool help compare suppliers or processes?
Yes. Apply consistent assumptions across lots, suppliers, lines, or shifts to compare rework exposure and identify the most expensive quality failure patterns.
7. What does cost per produced unit tell me?
It spreads total rework cost across the full batch. This helps pricing, margin analysis, and broader cost-of-quality reporting.
8. Is this a substitute for a full cost-of-quality system?
No. It is a focused estimator for corrective work. A full quality-cost system also tracks prevention, appraisal, scrap, complaints, and warranty impacts.