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Supplier Cost of Poor Quality Calculator

A supplier with a low piece price can be the most expensive one you buy from once rejects, sorting, expedites and stopped lines are counted. This calculator converts a reject rate and a few cost drivers into one annual number you can put next to the price quote.

Your numbers

Units received per year

units

Total quantity received from this supplier on this part or family in 12 months.

Unit price

Purchase price per unit, before freight.

Reject rate at receiving or line

1.2 %

Share of received units that are rejected, from incoming inspection or found later on the line.

Material credit from supplier

80 %

Share of rejected material value you actually recover through credit, replacement or RTV.

Handling cost per rejected unit

Sorting, containment, MRB time, paperwork, return freight, rework labor per rejected unit.

Expedite events per year

events

Premium freight or overtime events caused by rejects.

Average cost per expedite

Line-down hours per year

hours

Hours of lost or idle production attributed to this supplier's rejects.

Cost per line-down hour

$/hour

Your results

Total supplier cost of poor quality

$21,756

Annual hidden cost of this supplier's quality.

COPQ as percent of spend

2.1%

Compare this with the price gap to a better supplier.

Rejected units per year

1,440

Equivalent PPM

12,000

Parts per million rejected.

Unrecovered material loss

$2,448

Handling and containment cost

$4,608

Expedite cost

$2,700

Downtime cost

$12,000

Estimates only. Use your own measured handling time, expedite records and downtime attribution for decisions or supplier chargebacks.

Save results:

Annual supplier COPQ vs reject rate

Sweeps Reject rate at receiving or line from 0 to 8, holding your other inputs fixed.

Automate supplier COPQ from your ERP

Optional: a short review of how to pull receiving, NCR and purchase data into a live supplier cost view.

Optional. The tool and every export work without this. No spam.

How to use the calculator

Start with a single supplier and a single part or family so the data stays defensible. Pull units received and the reject rate from your ERP receiving and quality records. Estimate handling cost per rejected unit from the minutes spent on sorting, MRB, return paperwork and rework, multiplied by a loaded labor rate. Add expedite events and line-down hours only when you can tie them to a specific nonconformance report.

Use 12 months of data, not the worst quarter
Count rejects found on the line, not only at dock inspection
Set credit percent to what the supplier actually paid back
Leave downtime at zero if you cannot trace it to a cause

The method behind the numbers

This is a cost of poor quality build-up using the external failure and appraisal-adjacent categories that a buyer can see. Rejected units are units received times the reject rate. Material loss is only the part of the value you do not recover. Handling is per rejected unit, expedites are per event, and downtime is hours times your cost per hour. Total COPQ divided by purchase spend shows how many percentage points of hidden cost sit on top of the price.

Reading the result and the chart

The default case is 120,000 units at $8.50 with a 1.2 percent reject rate. That produces about 1,440 rejects, but the cost is dominated by handling, expedites and downtime rather than by the material itself. The chart sweeps the reject rate from zero to eight percent so you can see how quickly the cost climbs. Use it in a negotiation: a competitor priced 4 percent higher may still win on total cost.

Common mistakes

The most frequent error is counting only the scrapped material value. The second is double counting: if downtime already includes the expedite overtime, remove one. Finally, do not mix customer-found escapes into this number without adding warranty and customer cost separately. Feed the result into your supplier scorecard and your sourcing business case, and keep the assumptions visible so a supplier can challenge them with data.

Frequently Asked Questions

What reject rate should I use?

Use rejected quantity divided by received quantity over 12 months, from inspection and line rejects together. If you only have PPM, divide by 10,000 to get a percent. Do not use lot rejection rate, which counts lots, not pieces.

Should I include internal scrap caused by supplier material?

Yes, if the root cause is confirmed as supplier related. Put it in handling cost per rejected unit or raise the reject rate to include it. Keep a record of the NCR numbers so the figure survives a supplier review.

Is this the same as the cost of quality in ISO 9004?

It is related but narrower. This tool covers the external failure cost a supplier causes you. A full cost of quality model also includes prevention and appraisal costs, such as audits and incoming inspection labor.

Can I use it for a chargeback?

Only as a starting point. Contract terms decide what you can recover, and many agreements limit claims to the material value plus a fixed handling fee. Check your purchase order terms before sending a claim.

If you want this calculated automatically from your ERP receiving, NCR and purchase history instead of retyped, Netray can build a read-only view over your own data.

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