How is first pass yield calculated?

FPY equals units that pass on the first attempt divided by units that entered the operation, counting only good parts with no rework. If 1,000 units enter and 940 pass first time while 60 need rework, FPY is 94 percent, even if the reworked parts eventually pass. FPY deliberately excludes reworked units because rework is hidden cost and effort you want the metric to reveal.

What is the difference between FPY and rolled throughput yield?

FPY measures one operation; rolled throughput yield (RTY) is the product of every operation's FPY across the process. Four operations at 95, 98, 96, and 99 percent give an RTY of 0.95 x 0.98 x 0.96 x 0.99, about 88.5 percent. RTY is always lower than any single step and represents the real chance a unit passes the entire line with zero rework at any stage.

Why is rolled throughput yield lower than final yield?

Final test yield counts parts that pass at the end, including many that were reworked along the way, so it masks the hidden factory. RTY counts only parts that flowed straight through untouched. A line showing 97 percent final yield might have an RTY of 85 percent because rework at intermediate steps was invisible to final test. The gap between the two numbers is the cost of your rework loops.

What is a good first pass yield benchmark?

Per-operation FPY above 99 percent is strong; below 95 percent usually flags a problem worth investigating. For RTY, the answer depends on step count, since even excellent operations compound. Twenty steps at 99 percent each yield an 81.8 percent RTY. Judge a process against its own baseline and the number of operations rather than a single universal target that ignores process complexity.

How do I convert first pass yield to a sigma level?

Convert FPY to defects per million opportunities, then read the sigma level. A 93.3 percent FPY is about 66,800 DPMO, roughly 3.0 sigma. 99.38 percent maps to near 4.0 sigma, and 99.9997 percent (3.4 DPMO) is 6.0 sigma. Use RTY rather than final yield for the conversion so the sigma level reflects the whole process, including hidden rework, not just end-of-line inspection.

Which operation should I improve first?

Rank operations by the combination of lowest FPY and highest rework plus scrap cost, not by yield alone. A 96 percent operation scrapping $50 machined parts can cost more than a 90 percent operation reworking $2 assemblies. Because RTY multiplies, fixing the weakest step gives the largest lift to overall yield, so start where low FPY and high cost per defect overlap on the summary.

Quality and Inspection

First Pass Yield Spreadsheet Template

Calculate first pass yield by operation and across a multi-step process to identify where defects are generated and where rework occurs.

Overview

This template lets quality engineers and process improvement teams measure first pass yield at each operation and across a full multi-step process. You list operations in sequence, enter units in and units that pass on the first attempt, and the sheet computes FPY per step and rolled throughput yield for the line. A single end-of-line yield hides where quality is actually lost; a process that looks 90 percent good at final test may run three 96 percent operations that compound. This sheet exposes that.

Each operation row captures its name and sequence, units entering, and units passing versus units sent to rework or scrap. FPY per operation is good-first-pass units divided by units in. Multiplying every operation's FPY gives rolled throughput yield, the true probability a unit passes the whole process untouched. Rework cost per operation multiplied by rework quantity, plus scrap cost, rolls into a total cost summary, so low-yield steps are ranked by dollars, not just percentage.

Use it to baseline a line before a Six Sigma or kaizen project, documenting where yield is consumed. Enter one week of production data, then read the RTY to set a realistic improvement target. The operation with the lowest FPY and highest rework cost is your first project. Pair it with the First Pass Yield Calculator to model how lifting one 92 percent operation to 98 percent moves the rolled yield, before you commit resources to the fix.

What this template includes

Operation name and sequence
Units entering each operation
Units passing vs. units requiring rework or scrap
FPY per operation
Rolled throughput yield across all operations
Rework cost per operation input
Total rework and scrap cost summary

Suggested use case

Use this to baseline process quality before a Six Sigma or improvement project, or to document where in a process yield is being consumed.

How to use it

List each process operation in sequence.
Enter units in and units out (good on first pass) per operation.
FPY per operation calculates automatically.
Review rolled throughput yield to see cumulative process quality.
Focus improvement efforts on operations with lowest FPY.

Frequently Asked Questions

How is first pass yield calculated?: FPY equals units that pass on the first attempt divided by units that entered the operation, counting only good parts with no rework. If 1,000 units enter and 940 pass first time while 60 need rework, FPY is 94 percent, even if the reworked parts eventually pass. FPY deliberately excludes reworked units because rework is hidden cost and effort you want the metric to reveal.
What is the difference between FPY and rolled throughput yield?: FPY measures one operation; rolled throughput yield (RTY) is the product of every operation's FPY across the process. Four operations at 95, 98, 96, and 99 percent give an RTY of 0.95 x 0.98 x 0.96 x 0.99, about 88.5 percent. RTY is always lower than any single step and represents the real chance a unit passes the entire line with zero rework at any stage.
Why is rolled throughput yield lower than final yield?: Final test yield counts parts that pass at the end, including many that were reworked along the way, so it masks the hidden factory. RTY counts only parts that flowed straight through untouched. A line showing 97 percent final yield might have an RTY of 85 percent because rework at intermediate steps was invisible to final test. The gap between the two numbers is the cost of your rework loops.
What is a good first pass yield benchmark?: Per-operation FPY above 99 percent is strong; below 95 percent usually flags a problem worth investigating. For RTY, the answer depends on step count, since even excellent operations compound. Twenty steps at 99 percent each yield an 81.8 percent RTY. Judge a process against its own baseline and the number of operations rather than a single universal target that ignores process complexity.
How do I convert first pass yield to a sigma level?: Convert FPY to defects per million opportunities, then read the sigma level. A 93.3 percent FPY is about 66,800 DPMO, roughly 3.0 sigma. 99.38 percent maps to near 4.0 sigma, and 99.9997 percent (3.4 DPMO) is 6.0 sigma. Use RTY rather than final yield for the conversion so the sigma level reflects the whole process, including hidden rework, not just end-of-line inspection.
Which operation should I improve first?: Rank operations by the combination of lowest FPY and highest rework plus scrap cost, not by yield alone. A 96 percent operation scrapping $50 machined parts can cost more than a 90 percent operation reworking $2 assemblies. Because RTY multiplies, fixing the weakest step gives the largest lift to overall yield, so start where low FPY and high cost per defect overlap on the summary.