Scrap and Defect Rate

Excel Formulas › Manufacturing & Operations

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Scrap rate is defective units over total produced — the quality-cost signal on a production line. It drives material waste, rework, and yield, and is the easy win most lines chase first.


Quick formula: scrap rate from defects and total:
=defective_units / total_units
Defective units over total produced, as a percentage. The good-unit complement is the yield.

The example

18 defects of 1,200.

AB
1ItemValue
2Defects18
3Total1200 → 1.5%

The formula

The formula:

=B2 / B3 // defects ÷ total

How it works

How it works:

  1. Divide defective units by total produced for the scrap rate.
  2. The good-unit rate (yield) is 1 - scrap.
  3. Translate to cost: defects × cost_per_unit — the money lost to scrap.
  4. Track by defect type or station with COUNTIF to target the biggest contributor.

Scrap is cheaper to prevent than rework. Pareto the defects — COUNTIF by defect type, sorted — and usually a few causes drive most of the scrap. Fixing the top one or two moves the rate more than broad effort. Express the gain in dollars (defects × cost_per_unit) to justify the fix to finance.

Try it: interactive demo

Live demo

Defects and total units.

Scrap · Yield

Variations

Yield

Good rate:

=1 - defective_units / total_units

Scrap cost

Dollars lost:

=defective_units * cost_per_unit

By defect type

Pareto:

=COUNTIF(defect_type, "Crack") / total

Pitfalls & errors

Defects vs total. Divide by total produced, not just good units.

Scrap vs rework. Decide whether reworkable units count as scrap.

Zero produced. No units gives #DIV/0!.

Practice workbook

📊
Download the free Scrap and Defect Rate practice workbook
A scrap-rate sheet with the yield, cost, and by-type variants, plus 4 challenges with answers. No sign-up required.

Frequently asked questions

How do I calculate scrap rate in Excel?
Divide defective units by total produced: =defective_units / total_units. 18 of 1,200 is 1.5%.
How do I get yield from scrap rate?
Yield is the complement: =1 - defective_units / total_units.
How do I find the biggest defect cause?
Pareto with COUNTIF by defect type and sort — a few causes usually drive most scrap.

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Related formulas: First-pass yield · PPM defect rate · Shrinkage rate