First-pass yield (FPY)

First-pass yield measures how often a manufacturing or business process produces a correct, usable result the first time, without needing rework, repair, or scrapping. It is a stricter measure of process quality than a simple pass rate at final inspection, because a unit that failed and was later fixed still counts against first-pass yield even though it eventually shipped.

The formula is units produced correctly the first time / total units started × 100, calculated at a single process step. When a product passes through multiple steps, the overall yield is the product of each step's first-pass yield, often called rolled throughput yield, which is why a process with several 95%-yield steps can still have a surprisingly low end-to-end yield. This distinguishes it from a final-inspection pass rate, which can look healthy even when significant rework happened along the way.

Manufacturers track first-pass yield because rework and scrap are hidden costs, consuming labor and materials without producing sellable output, and it is a core metric in Six Sigma and statistical process control programs aimed at reducing process variation. It also feeds into the quality component of overall equipment effectiveness. A common pitfall is measuring first-pass yield only at final inspection rather than at each process step, which hides exactly where in the process defects are actually being introduced, information that also matters for interpreting mean time between failures trends on the equipment involved.