How do you calculate EOL first-pass yield?

Divide the units that pass EOL on the first attempt by the total units EOL tested, then multiply by 100. With 940 first-pass passes out of 1,000 tested, FPY is 940 ÷ 1,000 = 94%.

What is a good EV end-of-line first-pass yield?

Mature EV pack and vehicle EOL lines target 95–98% FPY; ramping lines often sit lower while test limits and assembly stabilize. At 94% against a 96% target the example line is 2 points short, meaning 20 of every 1,000 units need a rework or retest loop.

What is the difference between EOL first-pass yield and final yield?

First-pass yield counts only units that pass without intervention. Final yield includes units that pass after rework and retest. The gap between them is your rework burden — units that eventually ship but cost extra labor and cycle time.

Why does my EOL yield drop suddenly?

Common causes are an upstream process shift (torque, weld, or BMS firmware), a drifting or newly tightened EOL test limit, fixture or contact issues at the station, and intermittent communication faults during the BMS handshake.

How many units is the 2-point gap costing?

On 1,000 units tested, a 2-point FPY gap is 20 units routed to rework that should have passed clean. Multiply by the loaded cost of an EOL rework loop and your daily volume to size the opportunity.

Should retested units count in EOL yield?

For first-pass yield, no — count a unit as a pass only if it cleared EOL on attempt one. Track retest passes separately so you can see both true FPY and overall throughput yield.

EV & Battery Manufacturing calculator

EV End-of-Line Test Yield Calculator

EV end-of-line (EOL) test yield is the share of assembled packs, modules, or vehicles that pass the final EOL test station the first time, with no rework, retest, or diagnostic loop. It is the headline first-pass yield (FPY) that plant managers, quality engineers, and EOL station owners watch because every unit that fails here is fully built — cells, BMS, busbars, harness, enclosure — so a failure ties up the most labor and material of any defect in the line. EOL FPY drives takt, rework-bay loading, and warranty risk all at once, which is why it sits on nearly every EV assembly daily scorecard.

What this calculator does

Calculate first-pass EOL test yield for vehicles, packs, modules, or power electronics.
an EV assembly, battery pack, inverter, or charger line needs to track first-pass EOL test performance
It computes the fraction of EOL-tested units that pass on the first attempt as a percent, and the gap in points between that and your FPY target.

Formula used

EOL first-pass yield = units passing EOL first time ÷ total units EOL tested
EOL yield gap to target = target EOL yield - calculated yield

Inputs explained

Units passing EOL first time: Count vehicles, packs, modules, or electronics that pass without repair or retest.
Total units EOL tested: Use the matching tested population for the same line and period.
Target EOL first-pass yield: Use the production KPI or launch target for this product.

How to use the result

Use it per shift or per day at the EOL station, and break it down by failing test step when FPY drops below target.
First-pass yield says nothing about whether failures are real defects or false rejects from a marginal test limit — a tightened EOL spec can drop FPY without any change in product quality.

Current U.S. benchmarks

The producer price index for copper and brass mill shapes stands at 559.593 (BLS, May 2026), up 76.8% from a year earlier. Quotes priced off last quarter's material cost miss this move. Global copper trades at $13,484 per tonne (IMF via FRED, May 2026).
U.S. light vehicles sell at a 16.9 million annual rate (BEA, Jun 2026), up 4.1% from a year earlier, the volume signal for automotive supply chains.
Global copper trades at $13,484 per tonne (IMF via FRED, May 2026), up 41.5% in a year, and U.S. industrial electricity averages 8.66 cents per kWh. Both feed electrified-hardware unit economics.
The U.S. has 11,691 transportation equipment establishments employing about 1,682,910 workers (Census County Business Patterns, 2023).

Common questions

How do you calculate EOL first-pass yield? Divide the units that pass EOL on the first attempt by the total units EOL tested, then multiply by 100. With 940 first-pass passes out of 1,000 tested, FPY is 940 ÷ 1,000 = 94%.
What is a good EV end-of-line first-pass yield? Mature EV pack and vehicle EOL lines target 95–98% FPY; ramping lines often sit lower while test limits and assembly stabilize. At 94% against a 96% target the example line is 2 points short, meaning 20 of every 1,000 units need a rework or retest loop.
What is the difference between EOL first-pass yield and final yield? First-pass yield counts only units that pass without intervention. Final yield includes units that pass after rework and retest. The gap between them is your rework burden — units that eventually ship but cost extra labor and cycle time.
Why does my EOL yield drop suddenly? Common causes are an upstream process shift (torque, weld, or BMS firmware), a drifting or newly tightened EOL test limit, fixture or contact issues at the station, and intermittent communication faults during the BMS handshake.
How many units is the 2-point gap costing? On 1,000 units tested, a 2-point FPY gap is 20 units routed to rework that should have passed clean. Multiply by the loaded cost of an EOL rework loop and your daily volume to size the opportunity.

Last reviewed 2026-05-12.