How do you calculate line scrap rate?

Divide scrapped or rejected units by total units produced, then multiply by 100. With 185 scrapped out of 9,400 produced, that is 185 / 9,400 x 100 = 1.97% scrap.

What is a good scrap rate for a production line?

It depends on the process, but many discrete-assembly lines target 1-2% or lower, and tight food, pharma, or precision lines push under 1%. In the worked example a 1.97% actual rate sits just above a 1.5% target, a 0.47-point miss.

What does a negative gap to target mean?

Gap to target is target minus actual. A negative value, like the -0.47 points in the example, means your actual scrap rate is higher than your ceiling, so the line is failing the target and needs corrective action.

Scrap rate vs yield - what's the difference?

They are two sides of the same coin. Scrap rate is the share of output rejected; first-pass yield is the share accepted. A 1.97% scrap rate corresponds roughly to a 98.03% pass rate before any rework.

How many units is 1.97% scrap actually costing me?

At 1.97% on 9,400 units you lost 185 units of good output. Cutting that to the 1.5% target would have saved about 44 units on this run alone, which compounds fast across shifts.

Should rework be counted as scrap?

No. Scrap means units that cannot be sold or recovered. Reworked units that eventually pass should be tracked separately, otherwise you overstate true scrap and understate your rework burden.

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Scrap Impact on Line Output Calculator

Line scrap rate is the percentage of units a production line produces that get rejected or discarded instead of shipping as good product. Line supervisors, continuous-improvement engineers, and OEE analysts track it because scrap directly erodes throughput, raises unit cost, and consumes capacity you already paid for in labor, material, and conveyor time. On a high-speed line, even a fraction of a point of scrap can mean hundreds of lost units per shift. This calculator turns raw reject counts into a clean percentage and tells you whether you are above or below your acceptable scrap ceiling.

What this calculator does

Calculate how scrap or rejects reduce good line output versus the planned production count.
a quality or operations manager needs to quantify how much scrap is reducing finished output
It converts scrapped units and total produced units into a line scrap rate percentage, then compares that rate against your maximum acceptable scrap target.

Formula used

Line scrap rate = scrapped units ÷ total produced units × 100
Gap to target = target scrap rate − actual scrap rate

Inputs explained

Scrapped or rejected line units: Count units rejected before they can be shipped or passed downstream.
Total units produced by line: Use the same production window as the rejected count.
Maximum acceptable scrap rate: Use the quality target, quote assumption, or control-plan limit.

How to use the result

Use it at end of shift, end of run, or during a quality stand-up to quantify how much of the line's output was lost to rejects and whether that loss breached the target.
It treats every scrapped unit equally and counts only units rejected by this line; it does not weight scrap by material cost, downstream rework value, or defects that escape to the next operation.

Current U.S. benchmarks

The U.S. has 21,668 machinery manufacturing establishments employing about 1,086,146 workers (Census County Business Patterns, 2023).

Common questions

How do you calculate line scrap rate? Divide scrapped or rejected units by total units produced, then multiply by 100. With 185 scrapped out of 9,400 produced, that is 185 / 9,400 x 100 = 1.97% scrap.
What is a good scrap rate for a production line? It depends on the process, but many discrete-assembly lines target 1-2% or lower, and tight food, pharma, or precision lines push under 1%. In the worked example a 1.97% actual rate sits just above a 1.5% target, a 0.47-point miss.
What does a negative gap to target mean? Gap to target is target minus actual. A negative value, like the -0.47 points in the example, means your actual scrap rate is higher than your ceiling, so the line is failing the target and needs corrective action.
Scrap rate vs yield - what's the difference? They are two sides of the same coin. Scrap rate is the share of output rejected; first-pass yield is the share accepted. A 1.97% scrap rate corresponds roughly to a 98.03% pass rate before any rework.
How many units is 1.97% scrap actually costing me? At 1.97% on 9,400 units you lost 185 units of good output. Cutting that to the 1.5% target would have saved about 44 units on this run alone, which compounds fast across shifts.

Last reviewed 2026-05-12.