How do you calculate factory acceptance yield?

Divide machines passing FAT on the first pass by machines presented, then multiply by 100. With 17 of 20 machines passing first time, yield is 85%.

What is a good FAT first-pass yield?

For mature machinery lines, 90% or higher is a common target and 95%+ is strong. The example sits at 85% against a 90% target, a 5-point gap that signals a recurring build or test issue worth investigating.

What does the yield gap to target mean?

It is your actual yield minus your target, in percentage points. Here 85% against a 90% target is a 5-point shortfall, meaning one or two more machines per batch of 20 need to pass first time to hit goal.

First-pass yield vs final acceptance rate, what is the difference?

Final acceptance rate counts every machine that eventually passes after rework. First-pass yield, the 85% here, counts only those that passed without a re-test, which is the truer measure of process stability and schedule risk.

Why does first-pass FAT yield matter for ship dates?

Each first-pass failure means disassembly, fix, and a second FAT slot. The 3 failures in a batch of 20 can each cost days of schedule, so an 85% yield often translates directly into slipped deliveries.

How many more machines must pass to close a 5-point gap?

On a batch of 20, each machine is 5 points. Moving from 17 to 18 first-pass passes lifts yield from 85% to 90% and closes the gap exactly.

Industrial Equipment, Machinery & Capital Goods calculator

Factory Acceptance Yield Calculator

Factory Acceptance Yield measures the percent of machines that pass their Factory Acceptance Test on the first attempt, before any rework or re-test loop. Quality managers and program leads at machinery and capital-goods builders use it as the headline health metric for end-of-line acceptance, because a machine that fails FAT triggers expensive disassembly, re-test, and often a slipped ship date. It matters because first-pass yield, not eventual pass rate, is what protects your schedule and margin: every first-pass failure consumes a test slot twice and erodes customer confidence at the worst moment. Tracking it against a target tells you whether your build process is genuinely stable or quietly leaking defects into final acceptance.

What this calculator does

Calculate first-pass factory acceptance yield from machines passing FAT, machines presented for FAT, and target yield.
Use it when tracking how often equipment passes factory acceptance without major rework or retest.
It computes FAT first-pass yield as machines passing on the first attempt divided by machines presented, and the point gap to your target.

Formula used

Factory acceptance yield = machines passing FAT first pass ÷ machines presented for FAT × 100
Factory acceptance yield gap to target = factory acceptance yield - target FAT first-pass yield

Inputs explained

Machines passing FAT first pass:
Machines presented for FAT:
Target FAT first-pass yield:

How to use the result

Use it at end-of-line acceptance reviews to judge build quality and decide whether a line is meeting its first-pass goal.
It only counts first-pass outcomes, so a line that re-tests its way to 100% eventual acceptance can still show a poor first-pass yield here, which is by design.

Current U.S. benchmarks

The U.S. prime lending rate is 6.75% (Federal Reserve via FRED, 2026-07-02). Payback and financing math should start from today's rate, not a remembered one.
Steel mill PPI stands at 348.53 (BLS, May 2026), up 6.7% from a year earlier. New factory orders are up 2.3% year over year (Census).
The U.S. has 21,668 machinery manufacturing establishments employing about 1,086,146 workers (Census County Business Patterns, 2023).

Common questions

How do you calculate factory acceptance yield? Divide machines passing FAT on the first pass by machines presented, then multiply by 100. With 17 of 20 machines passing first time, yield is 85%.
What is a good FAT first-pass yield? For mature machinery lines, 90% or higher is a common target and 95%+ is strong. The example sits at 85% against a 90% target, a 5-point gap that signals a recurring build or test issue worth investigating.
What does the yield gap to target mean? It is your actual yield minus your target, in percentage points. Here 85% against a 90% target is a 5-point shortfall, meaning one or two more machines per batch of 20 need to pass first time to hit goal.
First-pass yield vs final acceptance rate, what is the difference? Final acceptance rate counts every machine that eventually passes after rework. First-pass yield, the 85% here, counts only those that passed without a re-test, which is the truer measure of process stability and schedule risk.
Why does first-pass FAT yield matter for ship dates? Each first-pass failure means disassembly, fix, and a second FAT slot. The 3 failures in a batch of 20 can each cost days of schedule, so an 85% yield often translates directly into slipped deliveries.

Last reviewed 2026-05-12.