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Overall Equipment Yield Loss Estimator

This estimator measures overall equipment yield loss from total produced units and defective units. It reports the defective share as the main result, alongside good yield, lost-unit count, and an optional direct value of the rejected output.

The tool is intended for equipment-level quality tracking where the same unit and defect definitions can be applied consistently across periods. A rising loss rate can signal a process issue worth investigating, but the calculation alone cannot identify whether the cause is equipment condition, material, setup, inspection, or another factor. Use the financial estimate as a simple unit-value view rather than a complete cost-of-poor-quality model.

Equipment quality data

units
units
USD
Result
—
equipment yield loss
Good yield—
Defective units—
Estimated direct loss—

1. Enter total equipment output
Use all units produced in the selected period under one consistent counting rule.

2. Enter defective output
Count units that fail the quality criterion used for this yield view.

3. Set an optional unit value
Use a direct value per defective unit if you want a simple loss estimate; enter 0 to focus on the physical yield metrics.

4. Review yield loss
The main percentage shows the defective share. Good yield is the remaining share of total output.

5. Track with stable definitions
Keep the product scope and defect rules consistent before comparing shifts, machines, or improvement periods.

Yield loss = Defective units ÷ Total units × 100 Good yield = (Total units − Defective units) ÷ Total units × 100 Direct loss estimate = Defective units × Value per unit

The value estimate assumes every defective unit loses the full entered unit value. Rework recovery, salvage, disposal expense, and downstream disruption are outside this simplified calculation.

What the result means

The main result is the percentage of total equipment output classified as defective for the selected period.

Use defect reason data and process evidence to investigate causes; the percentage alone does not distinguish machine, material, method, measurement, or human factors.

Given: 5,000 total units, 125 defective units, and $9.50 per unit.

Calculation: Yield loss = 125 ÷ 5,000 × 100 = 2.50%. Good yield = 97.50%. Direct loss = 125 × $9.50 = $1,187.50.

Result: Equipment yield loss is 2.50%, representing 125 defective units.

Interpretation: If the same equipment previously ran at 1.5% loss under comparable conditions, the increase warrants a defect-mode and process review rather than an assumption about cause.

Should scrap and rework both be counted as defective units?

That depends on the yield definition you are tracking. For first-pass quality, units needing rework are often treated as not-good; for final accepted yield, the treatment may differ.

Can I compare yield loss between machines?

Yes if they make comparable products and use the same inspection and defect criteria. Otherwise differences in product difficulty or measurement can dominate the comparison.

Why is the loss value only an estimate?

It multiplies defective units by one entered value. It does not separately model rework labor, salvage credit, disposal, warranty, delayed capacity, or downstream effects.

What if defective units equal total units?

Yield loss is 100% and good yield is 0%. That extreme result is mathematically valid but should prompt a check of the count scope and production event.

How does this relate to the quality factor in OEE?

OEE quality is good units divided by total units. Yield loss is the complement: defective units divided by total units, assuming the same counting definitions.