How do you calculate quality gate defect rate?

Divide the number of vehicles that failed the gate by the number inspected, then multiply by 100. With 14 defects found across 120 vehicles inspected, the rate is 14 ÷ 120 = 11.67%.

What is a good quality gate defect rate for bus and coach manufacturing?

It depends on the gate, but mature lines target low single digits at end-of-line gates and push in-process gates toward 2–5%. In the worked example a target of 5% against an actual 11.67% leaves a 6.67-point gap that needs containment.

What does the gap to target mean?

It is your actual rate minus your target rate in percentage points. Here 11.67% minus a 5% target is -6.67 points, meaning you are 6.67 points worse than target (the negative sign reflects actual exceeding target).

Is quality gate defect rate the same as first-pass yield?

They are mirror images at a single gate: first-pass yield is the share that passed clean, so a 11.67% defect rate equals roughly 88.33% first-pass yield at that gate, before any rework loop.

Why does one vehicle move the rate so much?

Bus and coach gates inspect small batches — 120 units here — so each unit is about 0.83 points. On a 30-unit daily gate one defect is over 3 points, which is why you read rate alongside the raw count.

Should I count a vehicle with multiple defects once or multiple times?

This calculator counts affected units, so a vehicle with three faults still counts as one. If you want defects-per-unit, track a separate defect count and divide by units inspected instead.

Commercial Vehicle, Bus & Coach Manufacturing calculator

Quality Gate Defect Rate Calculator

Quality Gate Defect Rate is the share of vehicles that fail a fixed inspection gate — for example chassis-to-body marriage, paint-out, or pre-delivery inspection — out of all units presented to that gate. On a bus and coach line it is the primary number plant quality managers and gate leaders watch shift by shift, because a defect caught at the gate is far cheaper than one found at the customer or in the field. It tells you whether upstream stations are stabilising or drifting, and it feeds directly into containment and rework decisions. Because coaches are low-volume, high-content builds, even a single bad unit moves this rate noticeably, so the number must always be read against the count behind it.

What this calculator does

Calculate defect rate at a commercial vehicle, bus, or coach quality gate.
measuring defects at a vehicle quality gate
It computes the percentage of inspected vehicles flagged with a defect at a specific quality gate, plus the gap in points to your target rate.

Formula used

Quality Gate Defect Rate = defects found at the quality gate ÷ vehicles inspected at the gate
Gap to target = Quality Gate Defect Rate - target quality gate defect rate

Inputs explained

Defects found at the quality gate:
Vehicles inspected at the gate:
Target quality gate defect rate:

How to use the result

Use it at each end-of-line or in-process gate to track first-time quality per shift, per gate, or per body type and to trigger containment when the rate breaches target.
It counts units that failed, not defects per unit or defect severity, so a single safety-critical fault and a minor trim blemish both count as one affected unit.

Current U.S. benchmarks

U.S. light vehicles sell at a 16.9 million annual rate (BEA, Jun 2026), up 4.1% from a year earlier, the volume signal for automotive supply chains.
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).
The U.S. has 11,691 transportation equipment establishments employing about 1,682,910 workers (Census County Business Patterns, 2023).

Common questions

How do you calculate quality gate defect rate? Divide the number of vehicles that failed the gate by the number inspected, then multiply by 100. With 14 defects found across 120 vehicles inspected, the rate is 14 ÷ 120 = 11.67%.
What is a good quality gate defect rate for bus and coach manufacturing? It depends on the gate, but mature lines target low single digits at end-of-line gates and push in-process gates toward 2–5%. In the worked example a target of 5% against an actual 11.67% leaves a 6.67-point gap that needs containment.
What does the gap to target mean? It is your actual rate minus your target rate in percentage points. Here 11.67% minus a 5% target is -6.67 points, meaning you are 6.67 points worse than target (the negative sign reflects actual exceeding target).
Is quality gate defect rate the same as first-pass yield? They are mirror images at a single gate: first-pass yield is the share that passed clean, so a 11.67% defect rate equals roughly 88.33% first-pass yield at that gate, before any rework loop.
Why does one vehicle move the rate so much? Bus and coach gates inspect small batches — 120 units here — so each unit is about 0.83 points. On a 30-unit daily gate one defect is over 3 points, which is why you read rate alongside the raw count.

Last reviewed 2026-05-12.