OEE Calculator
One Number, Three Ways a Machine Can Lose Time
Overall Equipment Effectiveness collapses three separate failure modes — the machine wasn't running, it ran slower than it should have, or it produced defective parts — into a single multiplicative score. That structure is deliberate: a machine can look fine on any one metric while OEE reveals a compounding problem across all three, since the score is a product, not an average.
The Formulas
From Raw Data:
Availability = (Planned Time − Downtime) / Planned Time
Performance = (Ideal Cycle Time × Total Count) / Operating Time
Quality = Good Count / Total Count
OEE = Availability × Performance × Quality
Worked Examples
| Mode | Inputs | Result |
|---|---|---|
| From percentages | Availability 90%, Performance 95%, Quality 99% | OEE = 84.65% |
| From raw data | Planned 480 min, downtime 45 min, ideal cycle 1.0 min/unit, total count 380, good count 361 | Availability 90.63%, Performance 87.36%, Quality 95.00%, OEE = 75.21% |
Because OEE multiplies three fractions together, even solid-looking individual numbers (90%+ on each) compound down to a noticeably lower combined score — that's the entire point of the metric.
Interpreting the Score
OEE benchmarking, going back to the Total Productive Maintenance framework the metric originates from, commonly cites 100% as a perfect score (only good parts, as fast as possible, with no stop time), around 85% as a widely-referenced "world class" target for discrete manufacturers, and OEE in the 40–60% range as typical for manufacturers that haven't yet focused on the metric.
Where This Matters
- Identifying the biggest lever — breaking OEE into its three components shows whether downtime, speed loss, or defects is the dominant drag, so improvement effort goes where it pays off most.
- Benchmarking equipment or lines — a consistent OEE calculation lets plants compare machines or shifts on equal footing.
- Justifying capital or process investment — a documented, trending OEE score is standard evidence in continuous-improvement and equipment-replacement proposals.
How to Use This Calculator
- Choose the mode: From Percentages or Detailed (Raw Data).
- For From Percentages: enter Availability, Performance, and Quality, each as a percent.
- For Detailed: enter Planned Production Time, Downtime, Ideal Cycle Time, Total Count, and Good Count.
- Select Calculate to see the availability, performance, and quality components plus the combined OEE score.
Related Calculations
Drill into the availability component with the Machine Utilization Calculator, or check the quality component with the Production Yield Calculator.