Free first pass yield calculator with rolled throughput yield
Calculate first pass yield (FPY) for every step of your production flow and the rolled throughput yield (RTY) of the whole process. Enter your process steps with a target FPY, then log the units tested and the units good the first time per process and shift, or paste the log from Excel.
FPY shows the hidden factory: every unit that needs rework, repair or a retest costs time and money even when it ships as a good part in the end. RTY shows how many units really get through the whole flow right the first time.
How the First Pass Yield (FPY) Calculator works
For each step the calculator adds up the units tested and the first-pass good units of the selected period. FPY is good divided by tested; RTY is the product of the FPYs of all steps. Each step gets the status OK, WATCH or ACTION against its target and the warning band.
Charts show FPY against target per step, the yield through the process flow, the daily RTY trend and a Pareto of the top defects. The verdict names the weakest step and compares RTY with the average FPY, which hides the loss.
When to use it
Use FPY and RTY for daily shift reports on the shop floor, weekly quality reviews, line and supplier comparisons, launch and run at rate monitoring, and to find the process step where rework and scrap cost the most. Many customers ask for FPY in the PPAP or in the quarterly quality review.
PDF report in one click
Create a first pass yield report as a PDF with the period, per-step table, RTY, charts, top defects and signature lines, ready for the quality meeting or the customer.
Private: everything runs in your browser
All data is processed and stored only in your browser. Nothing is uploaded to a server, there is no sign-up and no installation.
How to calculate first pass yield
FPY = first-pass good units / units tested. Count a unit as first-pass good only when it passed the step without rework, repair, retest or scrap. Do this for every step of the flow and for the same period.
RTY = FPY₁ × FPY₂ × … × FPYₙ. The rolled throughput yield is the probability that a unit goes through the whole process right the first time. It falls quickly: five steps at 96 % give an RTY of only 81.5 %.
Example
- Pre-assembly: 4,000 tested, 3,900 good → FPY 97.5 %
- Brazing: 3,950 tested, 3,720 good → FPY 94.2 %
- Final test: 3,900 tested, 3,840 good → FPY 98.5 %
- RTY = 0.975 × 0.942 × 0.985 = 90.4 %. The average FPY would show 96.7 % and hide the loss.
Reading the result
- Status per step: at or above target OK, within the warning band (default 2 points) WATCH, below it ACTION.
- Yield through the flow: the line chart shows how many units are still right first time after each step. The steepest drop is the step to work on first.
- Top defects: enter the main defect of each log line. The Pareto ranks defects by rejected units, the input for a 5 Why or an 8D.
Good practice
- Define for every step what counts as tested and what counts as first-pass good, and write it into the work instruction.
- Count retests and reworked units as failures, even if they pass later.
- Review FPY daily on the shop floor and the RTY trend weekly in the quality meeting.
- Put a cost on the losses with the COPQ calculator to get support for improvement projects.
Frequently asked questions
›What is first pass yield?
First pass yield (FPY) is the share of units that pass a process step right the first time, without rework, repair, retest or scrap. FPY = first-pass good units / units tested. Reworked parts that are good in the end still count as a failure for FPY.
›What is the difference between FPY and RTY?
FPY describes one process step. Rolled throughput yield (RTY) is the product of the FPYs of all steps in the flow and gives the probability that a unit passes the whole process right the first time. Three steps at 95 % each give an RTY of 85.7 %, not 95 %.
›Why not use the average FPY?
The average hides the loss. A unit has to pass every step, so the yields multiply. The average of 95 %, 95 % and 95 % is 95 %, but only 85.7 % of units get through all three without rework.
›What is a good first pass yield?
It depends on the product and the process. In automotive assembly, single steps often target 97 to 99.5 %, end-of-line tests 98 % or more. Set the target per step from the customer requirement and your current capability, then track the trend.
›Is FPY the same as final yield?
No. Final (or process) yield counts good units at the end, including reworked ones. FPY only counts units that were right the first time, so it shows the hidden factory of rework and repair that the final yield does not.
›Is the Excel template really free?
Yes. The FPY Report template (setup, daily log with 500 rows, report sheet with RTY, status and top defects) is free to download and use in your company. No sign-up.