How do you calculate First Pass Yield?

FPY = units passing first time ÷ units entering the process × 100. The SQL example on this page shows the same calculation against a simple table.

What commonly goes wrong when calculating First Pass Yield?

Counting reworked units as passed turns FPY into final yield, which is higher.

How to calculate First Pass Yield

First pass yield is the percentage of units that pass quality checks the first time, without rework or scrap.

Formula

FPY = units passing first time ÷ units entering the process × 100

SQL query

This example assumes: production_runs(id, line, started_units, passed_first_time). It is written in PostgreSQL syntax; date functions differ slightly in MySQL, BigQuery and SQLite, and your column names will differ from these.

SELECT line,
       SUM(passed_first_time) * 100.0 / NULLIF(SUM(started_units), 0) AS fpy_pct
FROM production_runs
GROUP BY line
ORDER BY fpy_pct;

Common mistakes that make First Pass Yield wrong

Counting reworked units as passed turns FPY into final yield, which is higher.
Multi-step processes multiply step yields (rolled throughput yield); do not average them.
Units still in progress should not be in the denominator.

Ask for First Pass Yield in plain English

Instead of writing the query yourself, you can type the question. SchemaChat turns it into SQL against your connected database or uploaded file, runs it, and shows the SQL and the figures it used so you can check the answer before you share it. It does not replace your judgement about the definition: check that the query matches the formula your business uses.

What is first pass yield by production line?
Which line has the most rework?

How to calculate First Pass Yield

Formula

SQL query

Common mistakes that make First Pass Yield wrong

Ask for First Pass Yield in plain English

Frequently asked questions