First Pass Yield Calculator
Find the share of units that passed with no rework of any kind.
What this calculator does
One division expressed as a percentage, with the complement shown as the share not passing first time.
Inputs and what they mean
- Units started
- — number value.
- Units passing first time
- — Units that met specification with no rework, repair, retest or reinspection..
How to use it
- Enter your own figures — the calculator never fills in a rate, price or benchmark for you.
- Press Calculate to see the result.
- Read the formula, variables, assumptions and source below the result before you rely on it.
Formula
FPY = (Units passing first time ÷ Units started) × 100
Worked example
462 of 500 units right first time
Units that needed rework are excluded from the pass count.
Reading the result
The headline figure is the main answer. Any breakdown underneath shows the parts that make it up, so you can check the working and see what changes when you adjust an input.
Limitations and assumptions
Results depend entirely on the figures you enter and are rounded for display. They are for general information and education, not professional advice.
Reference: American Society for Quality — Process capability and defect rate measures
Last reviewed:
Common questions
Formula, source and verification
The proportion of units that passed without rework, repair, retest or reinspection.
The question it answers: How much of our output is right first time, and how much survives every step?
The formula
FPY = (Units passing first time ÷ Units started) × 100
- P — Units passing first time
- (count). Units that met specification with no rework.
- S — Units started
- (count). Units entering the step or process.
Units: Counts in; percentage out.
What kind of calculation this is
Deterministic formula. The same inputs always give the same answer. The maths is fixed and does not depend on judgement.
Method
One division expressed as a percentage, with the complement shown as the share not passing first time.
Assumptions built into the result
- Mathematical: Reworked, repaired, retested and reinspected units are excluded from the pass count.
Figures this calculator will never guess for you
- No benchmark, target or 'world class' value is supplied or implied; the result describes only the figures entered.
- No rolled yield across steps is inferred from a single step's yield.
Limitations
- A final yield that counts reworked units as passes will read higher than first pass yield; the two are different measures.
- Arithmetic over the counts entered — it cannot tell whether the inspection behind them was complete or consistent.
Source and version
- Standard or reference
- First pass yield — ASQ (ASQ quality resources, yield measures: first pass yield excludes reworked units from the pass count.)
- Published source
- American Society for Quality — Quality resources
- Formula version
- Version 1
- Verification
- Reviewed against the cited source on
- How much weight the source carries
- Standards or government
- Applies to
- Currency
- The result is a ratio or index, so it does not depend on currency.
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