Rolled Throughput Yield (RTY) Calculator

About the Rolled Throughput Yield (RTY) Calculator

Rolled throughput yield (RTY) is the probability that a unit will pass through every step of a multi-step process without rework or rejection on any step. It is calculated by multiplying the first pass yield (FPY) of each sequential process step. RTY provides a far more accurate picture of overall process quality than final yield because it captures the cumulative impact of defects generated at every stage.

Consider a three-step process where each step has 95% FPY. The final yield might be 99% because rework salvages most defects, but the RTY is 0.95 × 0.95 × 0.95 = 85.7%. This means only 85.7% of units flow through the entire process without requiring any intervention — a much more honest assessment of process capability.

This calculator lets you enter FPY values for up to ten process steps and quickly computes the RTY, revealing the true end-to-end quality of your production line.

When This Page Helps

RTY reveals how much hidden rework exists in your total process. While final yield can mask quality problems, RTY shows the true probability of producing a defect-free unit end-to-end. It is essential for lean manufacturing and Six Sigma improvement projects.

How to Use the Inputs

1. Determine the first pass yield (FPY) for each process step.
2. Enter the FPY for step 1 as a percentage.
3. Enter FPY values for additional steps (up to 10).
4. Leave unused steps blank or at 100%.
5. Review the RTY result — the probability of a defect-free unit through all steps.
6. Identify the step with the lowest FPY as your top improvement target.

Example Calculation

Tips & Best Practices

• Always use FPY (not final yield) for each step — final yield inflates RTY by ignoring rework.
• Even small FPY improvements at each step compound into significant RTY gains.
• Focus improvement efforts on the process step with the lowest FPY for maximum RTY impact.
• Use RTY as a baseline before and after kaizen events to quantify improvements.
• Plot RTY over time to track the overall health of your production system.
• Compare RTY to final yield — a large gap indicates substantial hidden rework.

The Power of Compounding Yields

RTY's strength comes from its honesty. A manufacturing line with 20 steps, each at 99% FPY, has an RTY of only 81.8%. That means nearly 1 in 5 units needs rework somewhere in the process. Without RTY, this hidden factory remains invisible.

Using RTY for Improvement Prioritization

Rank process steps by their FPY from lowest to highest. The step with the lowest FPY offers the greatest leverage for improving RTY. Even a 2% FPY gain at the worst step often improves RTY more than a 5% gain at an already-strong step.

RTY in Lean and Six Sigma

Lean practitioners use RTY to quantify hidden waste (muda), specifically the waste of rework and over-processing. Six Sigma teams use RTY to calculate process sigma levels and set improvement targets during DMAIC projects.

Frequently Asked Questions

• What is the difference between RTY and final yield?

  Final yield only measures units that ultimately ship successfully; it includes reworked units. RTY multiplies first-pass yields and reveals the true defect-free probability. RTY is always less than or equal to final yield.

• How many process steps can RTY include?

  RTY can include any number of sequential steps. The more steps, the more RTY typically drops, since each step's imperfections multiply. This calculator supports up to 10 steps.

• Why does RTY drop so fast?

  Because yields are multiplied, not averaged. Five steps at 95% each give RTY = 0.95^5 = 77.4%, not 95%. This compounding effect is exactly why RTY is so revealing.

• What is a good RTY target?

  A good RTY depends on process complexity. For 3–5 step processes, 90%+ is a strong target. For 10+ step processes, 85%+ is excellent. Six Sigma organizations aim for RTY above 95% even in complex processes.

• Can parallel process steps be included in RTY?

  RTY is designed for sequential steps. For parallel paths that merge, calculate RTY for each path separately and then multiply the merged result at the convergence point.

• How does RTY relate to DPMO?

  Overall DPU (defects per unit) across the process equals −ln(RTY). You can then convert DPU to DPMO if you know the number of opportunities per unit, linking RTY to the sigma level of your process.