What is First Pass Yield (FPY)?

FPY is the percentage of units that complete a process step correctly on the first attempt, without rework or scrap. Formula: FPY = (units passed ÷ units started) × 100%.

What is Rolled Throughput Yield (RTY)?

RTY is the probability that a unit passes through all process steps without defects. It equals the product of the individual FPYs: RTY = FPY₁ × FPY₂ × … × FPYn. RTY is always lower than any single-step FPY.

How is Sigma level estimated from RTY?

DPMO (Defects Per Million Opportunities) is calculated as (1 − RTY) × 1,000,000. The Sigma level is then looked up from a standard conversion table. This is a single-opportunity approximation; multi-opportunity processes need an additional opportunities-per-unit divisor.

Why is RTY lower than individual step FPYs?

Each step introduces some probability of failure. Multiplying probabilities together means even small defect rates compound quickly across many steps. A 5-step process with 99% FPY each gives an RTY of about 95%.

DPMO stands for Defects Per Million Opportunities. It measures how many defects would be expected per million units processed, and is the standard input for Sigma level lookup tables.

Can I use this for non-manufacturing processes?

Yes. Any sequential process where you can count inputs and error-free outputs can be analyzed with FPY and RTY — software testing, order fulfillment, document processing, and more.

First Pass Yield (FPY) Calculator

Calculate First Pass Yield per process step and Rolled Throughput Yield (RTY) across up to 8 steps, with Sigma level estimation.

Process Steps

1 / 8 steps

Rolled Throughput Yield

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RTY

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DPMO

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Sigma Level

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Steps

Step-by-Step FPY

Enter step data on the left to see results.

Summary

Enter units started and units passed for each manufacturing process step. The tool calculates individual FPY, the overall Rolled Throughput Yield (RTY), and an estimated Sigma level based on DPMO.

How it works

Add one or more process steps using the "Add Step" button (up to 8 steps).
Enter the number of units started and units passed without rework for each step.
The calculator shows the FPY for each individual step as you type.
Rolled Throughput Yield (RTY) is calculated as the product of all step FPYs.
DPMO is derived from RTY: DPMO = (1 − RTY) × 1,000,000.
Sigma level is estimated from DPMO using a standard lookup table.

Use cases

Identify which manufacturing step has the lowest yield and focus improvement efforts there.
Compare RTY across production lines or product variants.
Estimate process Sigma level without a full DPMO study.
Track FPY trends after implementing process changes.
Report quality metrics to management or customers.
Set targets for Six Sigma improvement projects.

Frequently Asked Questions

Last updated: 2026-06-15 · Reviewed by Nham Vu