First pass yield calculator

Methodology

First-pass yield for a stage = units that passed first time ÷ units entering that stage. It counts only units that needed no rework, which is what separates it from a final acceptance rate. Rolled throughput yield multiplies every stage's first-pass yield together: it is the probability a unit passes the whole process without being touched twice, and it falls fast as stages are added even when each stage looks healthy. The hidden-factory gap is the difference between the final stage's yield and the rolled figure — the rework effort that a stage-by-stage view never shows, because each stage reports itself as fine after its own rework. Units to start for one thousand good divides the target by rolled yield, showing the material and capacity the process actually consumes to deliver a given quantity. Excluded: the cost of scrap and rework (use the scrap-rate calculator), inspection escapes reaching the customer, correlation between stage failures, and any distinction between a defect found at the station and one found downstream. You supply every input: this site holds no factory cost data, capacity figures, yields, cycle times or industry benchmarks, and never estimates them for you. Results are an orientation model for structuring a decision, not an industrial engineering study, a quotation, or safety, engineering or financial advice. Confirm equipment capability, staffing, process capability and cost with your own measurements before relying on them.