First Pass Yield Calculator

About this calculator

First pass yield (FPY) is a manufacturing quality metric that measures the percentage of units completing a process step correctly on the first attempt, with no rework, repair or scrap required: FPY = (units started − units needing rework or scrapped) ÷ units started, expressed as a percentage. Unlike a final yield figure that only counts units that eventually shipped, FPY exposes hidden cost by counting a reworked-then-passed unit as a failure of the first pass, since rework consumes extra time, labor and material even if the unit is ultimately saved.

FPY is a core metric in lean manufacturing and Six Sigma quality programs, used by production managers and quality engineers to spot which process step is generating the most defects and to track whether process improvements are actually reducing rework rather than just catching more defects downstream. When a process has multiple sequential steps, multiplying each step's FPY together gives the rolled throughput yield, a stricter measure of true end-to-end process quality.