# Rolled Throughput Yield and Rework Cost Calculator > Source: https://netray.co/tools/end-of-line-rolled-throughput-yield-calculator > Publisher: Netray (netray.co), AI and integration engineering for ERP and manufacturing systems. > Section: Free Tools ## Short answer Compute rolled throughput yield from the first time through yield of five steps, plus the starts required and the cost of rework. ## Category quality ## Industry Automotive ## Audience - Quality engineer - Process engineer - Plant manager ## Tool **Kind:** calculator **Currency:** $ **Inputs:** #### Step 1 first time through yield **Key:** s1 **Type:** number **Default:** 99.2 **Min:** 0 **Max:** 100 **Step:** 0.1 **Unit:** % #### Step 2 first time through yield **Key:** s2 **Type:** number **Default:** 98.5 **Min:** 0 **Max:** 100 **Step:** 0.1 **Unit:** % #### Step 3 first time through yield **Key:** s3 **Type:** slider **Default:** 96 **Min:** 80 **Max:** 100 **Step:** 0.5 **Unit:** % **Help:** The weakest step is a good one to sweep. #### Step 4 first time through yield **Key:** s4 **Type:** number **Default:** 99 **Min:** 0 **Max:** 100 **Step:** 0.1 **Unit:** % #### Step 5 first time through yield **Key:** s5 **Type:** number **Default:** 98 **Min:** 0 **Max:** 100 **Step:** 0.1 **Unit:** % #### Good parts required per month **Key:** good **Type:** number **Default:** 40000 **Min:** 0 **Step:** 500 **Unit:** pcs #### Average cost per failed first pass **Key:** rework **Type:** number **Default:** 3.4 **Min:** 0 **Step:** 0.1 **Unit:** $ **Help:** Rework, retest, handling or scrap loss per part that fails a step. **Outputs:** #### Rolled throughput yield **Key:** rty **Expr:** s1 / 100 * s2 / 100 * s3 / 100 * s4 / 100 * s5 / 100 * 100 **Format:** percent **Primary:** true **Description:** Probability a part passes every step with no rework. #### Starts needed for good parts **Key:** starts **Expr:** if(gt(rty, 0), good / (rty / 100), 0) **Format:** integer #### Extra units processed because of loss **Key:** extra **Expr:** starts - good **Format:** integer #### Failed first pass events per month **Key:** fails **Expr:** starts * (1 - s1 / 100) + starts * s1 / 100 * (1 - s2 / 100) + starts * s1 / 100 * s2 / 100 * (1 - s3 / 100) + starts * s1 / 100 * s2 / 100 * s3 / 100 * (1 - s4 / 100) + starts * s1 / 100 * s2 / 100 * s3 / 100 * s4 / 100 * (1 - s5 / 100) **Format:** integer #### Monthly hidden factory cost **Key:** hidden **Expr:** fails * rework **Format:** currency **Primary:** true #### Annual hidden factory cost **Key:** annual **Expr:** hidden * 12 **Format:** currency **Chart:** #### Rolled throughput yield vs step 3 yield **Type:** line **X:** s3 **From:** 80 **To:** 100 **Steps:** 21 **Series:** - rty **Disclaimer:** Assumes failed first pass parts are reworked or scrapped outside the normal flow and that steps are independent. ## Content **Intro:** 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. **Sections:** #### How to use it **Body:** 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. **Bullets:** - 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 **Body:** 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 **Body:** 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 **Body:** 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. **Cta:** 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. **Faq:** #### What is the difference between RTY and final yield? **Answer:** 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? **Answer:** 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? **Answer:** 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? **Answer:** 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. ## Search terms rolled throughput yield calculator, RTY calculator, first time through yield calculator, FTT yield multiply stations, hidden factory rework cost, process yield automotive line, end of line yield calculation --- Talk to an engineer: https://netray.co/contact?intent=erp_ai | Machine catalog: https://netray.co/agent/catalog.json