OEE Calculator (Overall Equipment Effectiveness)

Calculate overall equipment effectiveness from availability, performance, and quality — the standard manufacturing productivity measure.

⚙️ Operations📐 OEE = availability × performance × quality💼 Business
Planned production time (minutes)
Downtime (minutes)
Total units produced
Ideal cycle time (minutes per unit)
Defective or rejected units
Please enter valid values.

Formula & Reference

VariableSymbolFormulaUnits
OEE Calculator (Overall Equipment Effectiveness)OEE = availability × performance × qualitypercent

Step-by-Step Examples

Example 1
Typical Operation

480 min planned, 47 min downtime, 19,271 units, 0.02 min ideal cycle, 423 defects.

  • Run time = 480 − 47 = 433 min
  • Availability = 433 / 480 = 90.2%
  • Performance = (0.02 × 19,271) / 433 = 89.0%
  • Quality = (19,271 − 423) / 19,271 = 97.8%
  • OEE = 0.902 × 0.890 × 0.978 = 78.5%
✓ OEE 78.5% — good
Example 2
Downtime Problem

480 min planned, 160 min downtime, 12,000 units, 0.025 min cycle, 100 defects.

  • Availability = 320 / 480 = 66.7%
  • Performance = (0.025 × 12,000) / 320 = 93.8%
  • Quality = 99.2%
  • OEE = 62.0% — availability is the constraint
✓ OEE 62.0% — availability-limited
Example 3
Quality Problem

480 min planned, 30 min downtime, 20,000 units, 0.02 min cycle, 3,000 defects.

  • Availability = 93.8%, Performance = 88.9%
  • Quality = 17,000 / 20,000 = 85.0%
  • OEE = 70.9% — quality is dragging the result
✓ OEE 70.9% — quality-limited

Real-World Applications

Common Mistakes to Avoid

⚠️
Comparing OEE across different machines or plants

OEE depends on how planned production time is defined. Two sites using different definitions produce incomparable numbers.

⚠️
Excluding planned downtime to inflate the score

Removing changeovers and maintenance from planned time raises OEE without improving anything. Consistency matters more than the headline figure.

⚠️
Chasing 100% OEE

World class is around 85%. Pushing beyond that typically means running equipment without adequate maintenance, which fails later.

Frequently Asked Questions

What is OEE?
Overall equipment effectiveness — the product of availability, performance, and quality rates, measuring what proportion of planned production time is truly productive.
What is a good OEE score?
85% is generally considered world class for discrete manufacturing, 60% typical, and below 40% indicative of substantial improvement opportunity.
What are the six big losses?
Breakdowns and setup losses affect availability; idling and reduced speed affect performance; defects and startup rejects affect quality.
Should planned maintenance count as downtime?
Conventionally it is excluded from planned production time rather than counted as downtime, but the definition must be applied consistently to allow comparison.
Why can OEE be misleading?
Because it measures equipment efficiency, not business value. Running a machine efficiently to build inventory nobody has ordered raises OEE while destroying cash.

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