First Pass Yield Calculator
First pass yield, or FPY, is the share of units that pass a process step correctly the first time, with no rework and no scrap. It is a sharper quality measure than final yield because it exposes the hidden cost of rework that eventually ships as good. To compute it you enter the number of units that started the step and the number that passed first time. This calculator returns first pass yield as a percentage, the implied defect count, and the scrap or rework rate so you can quantify the loss.
First pass yield formula
First pass yield = (units passed first time / units started) * 100
Defective units = units started - units passed first time
Scrap / rework rate = 100 - first pass yield
Units passed first time must exclude anything that needed rework, even if it eventually passed. The complement of yield is the loss rate to defects.
Using first pass yield
- FPY measures right-first-time quality, not eventual quality after rework.
- Across a multi-step process, step yields multiply into rolled throughput yield.
- A high final yield with low FPY signals expensive hidden rework.
- Track FPY per step to find where defects originate.
- Six Sigma methods, referenced by NIST quality guidance, aim for very high per-step yields.
First pass yield: frequently asked questions
What is first pass yield?
First pass yield (FPY), also called throughput yield, is the proportion of units that pass a process step correctly the first time, without any rework or scrap. It equals good units passed first time divided by units that entered the step.
How is first pass yield different from final yield?
Final yield counts every unit that eventually ships, including those that needed rework. First pass yield counts only units that were right the first time, so it captures hidden rework cost that final yield hides.
How do I calculate first pass yield?
Divide the number of units that passed first time (no rework, no scrap) by the number of units that entered the process, then multiply by 100. For example, 950 good units out of 1,000 started gives a first pass yield of 95%.
What is a good first pass yield?
Higher is better and the practical target varies by industry and process complexity. There is no universal benchmark. Six Sigma quality programs target very high yields per step because yields multiply across a multi-step process.
Why does first pass yield matter?
Rework and scrap consume time, materials, and capacity without adding output. A low first pass yield means hidden cost. Improving it raises effective capacity and lowers cost per good unit without adding equipment.
Official sources
- U.S. National Institute of Standards and Technology: NIST/SEMATECH e-Handbook of Statistical Methods.
- U.S. National Institute of Standards and Technology: Manufacturing Extension Partnership.
Reviewed by the CalculatorHub team, edited by James Graham, 16 June 2026. See our methodology.