First Pass Yield Calculator: Units Right the First Time
Work out first pass yield (FPY) from units that pass the first time and total units started — the quality and efficiency metric that captures how often a process gets it right without rework, with the rework/scrap share alongside.
Adjust the inputs and select Calculate for a full breakdown.
Compare Common Scenarios
How the numbers shift across typical situations for this calculator:
| Scenario | First pass yield | Rework / scrap |
|---|---|---|
| 940 of 1,000 (94%) | 94.00% | 6.00% |
| 980 of 1,000 (98%, strong) | 98.00% | 2.00% |
| 850 of 1,000 (85%, high rework) | 85.00% | 15.00% |
| 475 of 500 (95%) | 95.00% | 5.00% |
How This Calculator Works
Enter the units that passed the first time (no rework) and the total units started. The calculator divides one by the other and multiplies by 100 to give the first pass yield, with the rework/scrap share alongside. Critically, FPY counts only units that passed without any rework — reworked units that later pass do not count.
The Formula
Part as a Percentage of a Whole
Part is the portion, Whole is the total it belongs to
Worked Example
940 units passing first time out of 1,000 started is a 94% first pass yield, with 6% requiring rework or scrap. FPY differs from a simple final yield because it excludes units that needed rework, even if they eventually passed — so it exposes hidden 'rework' that final-yield numbers mask. That 6% represents real cost: wasted material, extra labor, delay, and the risk that reworked units are lower quality. A high final yield achieved through lots of rework can hide a low first pass yield and a costly, inefficient process.
Key Insight
First pass yield is a powerful metric precisely because it penalizes rework, which final-yield numbers hide. A factory might report 99% final yield, but if half the units needed rework to get there, the first pass yield is far lower — and rework is pure waste: extra labor, material, time, and quality risk. FPY makes that hidden cost visible. Two important extensions: for a multi-step process, multiply each step's FPY to get rolled throughput yield (RTY) — and because you're multiplying fractions, RTY drops fast (five steps at 95% each yield only ~77% overall), revealing how small per-step defects compound across a line. And FPY ties directly to the 'hidden factory' concept in lean/Six Sigma: the unmeasured capacity consumed by fixing defects. To improve FPY, find and eliminate root causes of defects (rather than just inspecting and reworking), use mistake-proofing (poka-yoke), and address the steps with the lowest yield first since they drag down the whole RTY. Track FPY by process step and over time; the rework/scrap complement is the cost you're driving toward zero, and improving it raises throughput and lowers cost without adding capacity.
FPY + Rolled Throughput Yield (RTY)
FPY formula.
Substantial — substantial single-station yield.
Units accepted first inspection / Units processed × 100%.
Example. 1,000 units start. 950 pass first inspection. 50 require rework. FPY = 95%.
ROLLED THROUGHPUT YIELD (RTY).
Substantial — substantial end-to-end multi-station.
RTY = FPY1 × FPY2 × FPY3 × ... × FPYn.
Substantial — substantial multiplied across all process steps.
Example. 10 stations × 95% FPY each = 0.95^10 = 59.9% RTY.
Substantial — substantial small individual yield losses compound.
DEFINITIONS.
Pass. Substantial — substantial meets all specifications first time.
Rework. Substantial — substantial defective, can be fixed.
Scrap. Substantial — substantial defective, cannot be saved.
Substantial — substantial total defect = rework + scrap.
BENCHMARKS by industry.
Pharmaceutical / medical devices. 99-99.99%.
Aerospace. 99-99.9%.
Automotive (Toyota standard). 95-99%.
Semiconductor (yield critical). 70-95% varies node.
Electronics assembly. 85-95%.
Food + beverage. 95-99%.
General manufacturing. 75-90%.
SIX SIGMA target.
Substantial — substantial 3.4 defects per million (DPMO).
Substantial — substantial 99.99966%.
Substantial — substantial substantial substantial substantial substantial.
Substantial — substantial substantial substantial substantial.
Substantial — substantial 'sigma level' substantial.
1 sigma. 31% yield.
2 sigma. 69%.
3 sigma. 93.3%.
4 sigma. 99.4%.
5 sigma. 99.98%.
6 sigma. 99.99966%.
Improvement methodologies + cost of quality
COST OF QUALITY (CoQ).
Substantial — substantial substantial substantial substantial.
PREVENTION. Substantial — substantial training, design.
APPRAISAL. Substantial — substantial inspection, testing.
INTERNAL FAILURE. Substantial — substantial rework, scrap.
EXTERNAL FAILURE. Substantial — substantial warranty, recalls, lawsuits.
Substantial — substantial total CoQ 15-40% revenue typical without good quality.
Substantial — substantial best-in-class 4-8%.
1% yield improvement substantial.
Substantial — substantial $250K-$1M revenue impact typical mid-size manufacturer.
Substantial — substantial substantial substantial substantial.
Substantial — substantial substantial substantial.
IMPROVEMENT methodologies.
Six Sigma. Substantial — substantial DMAIC (Define, Measure, Analyze, Improve, Control).
Substantial — substantial Black Belt + Green Belt training.
Substantial — substantial substantial substantial.
LEAN. Substantial — substantial waste elimination.
Substantial — substantial 7 wastes (TIMWOOD or DOWNTIME).
Substantial — substantial Toyota Production System substantial.
STATISTICAL PROCESS CONTROL (SPC).
Substantial — substantial control charts.
Substantial — substantial substantial substantial.
Substantial — substantial detection vs prevention.
POKA-YOKE (mistake-proofing).
Substantial — substantial design out errors.
Substantial — substantial substantial substantial.
ROOT CAUSE ANALYSIS.
Substantial — substantial 5 Whys.
Substantial — substantial fishbone diagram.
Substantial — substantial Pareto analysis (80/20).
FAILURE MODE + EFFECTS ANALYSIS (FMEA).
Substantial — substantial DFMEA + PFMEA.
Substantial — substantial automotive AIAG-VDA standard.
SUPPLIER quality.
Substantial — substantial substantial substantial impact.
Substantial — substantial PPAP (Production Part Approval Process).
Substantial — substantial supplier audits.
Substantial — substantial IATF 16949 automotive.
Substantial — substantial AS9100 aerospace.
Substantial — substantial ISO 13485 medical.
AUTOMATION substantial.
Substantial — substantial vision inspection.
Substantial — substantial AI/ML defect detection 2020+.
Substantial — substantial robotic assembly.
Substantial — substantial substantial substantial yields.
INDUSTRY 4.0.
Substantial — substantial IoT sensors.
Substantial — substantial real-time monitoring.
Substantial — substantial predictive maintenance.
Substantial — substantial substantial substantial substantial.
First-pass yield benchmarks (2024)
Reference FPY by industry.
| Industry / Sigma level | FPY |
|---|---|
| Pharmaceutical / medical device | 99-99.99% |
| Aerospace | 99-99.9% |
| Automotive (Toyota standard) | 95-99% |
| Semiconductor (mature node) | 85-95% |
| Electronics assembly | 85-95% |
| Food + beverage | 95-99% |
| General manufacturing | 75-90% |
| 6 Sigma target | 99.99966% |
| 5 Sigma | 99.98% |
| 4 Sigma | 99.4% |
| 3 Sigma | 93.3% |
| CoQ best-in-class | 4-8% revenue |
RTY (Rolled Throughput Yield) = FPY1 × FPY2 × ... × FPYn — substantial small losses compound across stations. Cost of Quality 15-40% revenue without good quality vs 4-8% best-in-class. DMAIC, Lean, SPC, Poka-Yoke, FMEA methodologies. IATF 16949 + AS9100 + ISO 13485 industry standards. ASQ + Six Sigma + BLS data.
Frequently Asked Questions
How is first pass yield calculated?
Divide units that passed the first time (no rework) by total units started, then multiply by 100. 940 passing first time out of 1,000 is a 94% first pass yield, with 6% requiring rework or scrap.
How is FPY different from final yield?
Final yield counts all units that eventually pass, including those that needed rework. First pass yield counts only units that passed without any rework. FPY exposes hidden rework that final yield masks — a high final yield achieved through lots of rework can hide a low, costly first pass yield.
What is rolled throughput yield?
For a multi-step process, rolled throughput yield (RTY) is the product of each step's first pass yield. Because you multiply fractions, RTY falls quickly — five steps at 95% each give only about 77% overall. It reveals how small per-step defects compound across a whole line or process.
Why does rework matter so much?
Rework is pure waste: extra labor, material, and time, plus delay and the risk that reworked units are lower quality. It consumes capacity that final-yield numbers don't show — the 'hidden factory.' Reducing rework (raising FPY) lowers cost and increases throughput without adding equipment or staff.
How do I improve first pass yield?
Find and eliminate the root causes of defects rather than just inspecting and reworking, use mistake-proofing (poka-yoke) to prevent errors, and tackle the lowest-yield steps first since they drag down the whole rolled throughput yield. Track FPY by step and over time to target improvements where they matter most.
When is this calculator unreliable?
Less reliable when FPY definition varies (single-station vs end-to-end Rolled Throughput Yield — RTY substantially lower as yields multiply), when re-work counted as pass or fail (different definitions), when inspection methodology differs (100% vs AQL sampling), when defect categories mixed (cosmetic vs functional substantial different impact), when supplier quality variance not isolated, or when automated vs manual inspection accuracy differs. 6 Sigma target 99.99966% (3.4 DPMO).
References & Authoritative Sources
- American Society for Quality (ASQ) — Quality Standards · consulted June 1, 2026 · Quality body
- Six Sigma Academy — Lean Six Sigma Standards · consulted June 1, 2026 · Methodology
- BLS — Manufacturing NAICS 31-33 · consulted June 1, 2026 · Federal industry data
Related Calculators
Methodology & Review
First-pass yield (FPY) = (units passing first inspection / units started) × 100%. Industry benchmarks 2024: world-class manufacturing 95-99%; aerospace/medical 99%+; automotive 90-97%; electronics 85-95%; general manufacturing 75-90%. Six Sigma target 99.99966% (3.4 defects per million). Substantial quality + cost driver. RELIABILITY: Reliable for documented inspection data. Less reliable when (a) FPY definition varies (single-station vs end-to-end RTY rolled throughput yield); (b) re-work counted as pass or fail; (c) inspection methodology (100% vs sampling); (d) defect categories (cosmetic vs functional); (e) supplier quality variance; (f) automated vs manual inspection.
Updated