First Pass Yield Calculator
First pass yield at each step and the rolled throughput yield across a whole process — the share of units that get through every step right first time, which is far lower than any single step suggests.
First pass yield is the share of units that pass a step without rework.
How the first pass yield calculator works
First pass yield is the share of units that pass a step without rework. Rolled throughput yield multiplies the steps: five steps at 95% each give 77%, not 95%. That compounding is why a process of good-looking steps can still scrap or rework a quarter of everything it makes.
The hidden factory — the rework that keeps final yield high — is invisible in final inspection and visible only here.
Formula: RTY = Π FPY_i
Worked examples
| Inputs | Rolled throughput yield | Note |
|---|---|---|
| Five steps at 92 to 99% | 82.252% | RTY 82% |
| Every step at 95% | 77.378% | 77% — not 95% |
| Two excellent steps | 99.003% | 99% |
FAQFrequently asked questions
What is first pass yield?
The share of units that pass a step without rework or scrap. Final yield after rework can be much higher, which is exactly what hides the problem.
What is rolled throughput yield?
The product of every step's first pass yield — the share that gets through the whole process right first time. It is always lower than the worst step.
Why does it matter if final yield is fine?
Because rework costs money, capacity and time, and none of it shows in final inspection. RTY measures the hidden factory.
Which step should I fix?
The weakest, almost always. The result row shows what lifting it to 99% does to the whole process.
What is a good RTY?
Above 90% is good for a multi-step process; world-class assembly lines exceed 95. Below 75% the rework loop is a second production line.
Where these figures come from
- Nakajima (1988) — Introduction to TPM — the origin of Overall Equipment Effectiveness and its six big losses
- Safe Work Australia — the national work health and safety body
Last checked: September 2026. Definitions follow standard operations-management practice; where plants commonly differ, the page says so.