Rolled Throughput Yield and Rework Cost Calculator
A line where every step looks fine on its own can still lose a lot of parts overall. Rolled throughput yield multiplies first time through yield across the steps and exposes the cost of rework and retest that final yield figures hide.
Your numbers
The weakest step is a good one to sweep.
Rework, retest, handling or scrap loss per part that fails a step.
Your results
Assumes failed first pass parts are reworked or scrapped outside the normal flow and that steps are independent.
Rolled throughput yield vs step 3 yield
Sweeps Step 3 first time through yield from 80 to 100, holding your other inputs fixed.
First pass yield reporting from your ERP
Optional: discuss pulling first pass test results and rework data into a single report.
Optional. The tool and every export work without this. No spam.
How to use it
Enter first time through yield for each of five steps. First time through counts a part as good only if it passes without rework, retest or adjustment, which is stricter than final yield. Then set the number of good parts you need per month and the average cost of a failed first pass. Use the chart to sweep the weakest step.
- Take FTT from the first pass record, not the final count
- Count rework and retest as failures
- Use the same time window for every step
Formula
Rolled throughput yield equals the product of the step yields. With five steps at 99.2, 98.5, 96, 99 and 98 percent, RTY is about 91 percent. Starts needed equals good parts divided by RTY. Failures at each step are computed on the units that reach it, then multiplied by the average rework cost to give the hidden factory cost.
Reading the result
RTY is always at or below the lowest step yield, and it falls fast as steps are added. The chart shows how much the overall yield moves when the weakest step improves. Compare the annual hidden cost with the investment for fixing that step, such as a fixture, sensor or poka-yoke, to prioritize improvement work.
Common mistakes
Averaging step yields instead of multiplying them gives a falsely high figure. Mixing final yield at one step with first time yield at another breaks the math. Also remember that a step with automatic retest may report high final yield while hiding frequent first pass failure.
Frequently Asked Questions
What is the difference between RTY and final yield?
Final yield counts parts that eventually pass, including after rework. RTY counts only parts that pass every step the first time, so it reveals the hidden factory of rework and retest.
Can I use more than five steps?
This tool has five. For more steps, combine adjacent steps by multiplying their yields into one entry, or multiply all the yields in a spreadsheet and enter the result in step 1.
Is RTY the same as OEE quality?
Not exactly. OEE quality is usually measured at one point of the line, while RTY is a chain across steps. They are related but answer different questions.
What cost should I use per failure?
Include labor, test time, material and handling for the typical rework path, and add scrap value for parts that cannot be reworked. Weight by how often each outcome occurs.
Netray can help extract first pass test and rework records from your ERP or MES so RTY is calculated for every line and shift without manual data gathering.
Related Tools
Required OEE for OEM Volume Calculator
Back solve the OEE a cell needs to deliver a customer volume plus flex, and see the headroom or shortfall at your current OEE.
Supply Chain & InventoryCustomer Bank Build Stock Calculator
Size a finished goods bank requested by the customer, then see the extra run hours, calendar days to build it and the cost of holding it.
Costing & FinanceOEM Annual Price Down Margin Erosion Calculator
Model a yearly contractual price reduction against material and conversion cost savings and see where piece margin lands in each program year.
Engineering & PLMBattery Pack Series Parallel Configuration Calculator
Enter series and parallel counts and cell data to get pack voltage, Ah, kWh, cell count, cell mass and power at a chosen C rate.
More Quality & Inspection tools
See all- PPAP Submission Level Requirements Reference
- PPAP Part Submission Warrant Template
- APQP Timing Plan Worksheet
- IATF 16949 Internal Audit Checklist
- Run at Rate Calculator
- PPAP Dimensional Results Worksheet
- Customer Specific Requirements Matrix Worksheet
- APQP Phase Gate Checklist
- PFMEA Worksheet with RPN for PPAP