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OEE Calculator

OEE measures how much of your planned production time is truly productive. It combines three factors — availability, performance, and quality — into a single percentage [1]. World-class OEE is 85%. Most plants sit around 60% and don't realize how much capacity they're leaving on the table. Enter your shift data below to find out where you stand.

Total scheduled production time per shift, excluding planned breaks and maintenance. One standard shift is 480 minutes (8 hours).

Total minutes lost to breakdowns, changeovers, material shortages, and other unplanned stops during the shift.

The fastest possible time to produce one unit under optimal conditions. Check your machine's nameplate speed or best recorded run.

All units produced during the shift, including defective and reworked pieces.

Units that passed quality inspection on the first attempt, without rework. This is your first-pass yield count.

Overall Equipment Effectiveness

83.3%

OEE Components

Availability90.6%
Performance97.7%
Quality94.1%

How OEE Is Calculated

OEE is the product of three independent ratios: Availability, Performance, and Quality. Each captures a different type of production loss. Multiplying them together gives you the true picture of how effectively your equipment turns planned time into good output — a methodology developed by Seiichi Nakajima as part of TPM [2].

1

Calculate Availability

Availability = Run Time / Planned Production Time. Run Time is planned time minus all unplanned stops. This captures losses from breakdowns, changeovers, and material shortages.

2

Calculate Performance

Performance = (Ideal Cycle Time x Total Pieces) / Run Time. This measures speed losses: slow cycles, small stops, and running below nameplate capacity.

3

Calculate Quality

Quality = Good Pieces / Total Pieces. This captures yield losses: defects, rework, and startup scrap that consume run time without producing sellable output.

4

Multiply for OEE

OEE = Availability x Performance x Quality. A score of 85% is world-class. Below 60% means more than 40% of your planned capacity is being lost to some combination of stops, slow running, and defects.

Frequently Asked Questions

An OEE of 85% is considered world-class for discrete manufacturers. Most plants operate between 55-65% [1]. An OEE below 40% usually signals systemic issues with equipment reliability or process control. Improvement of even 5 percentage points can represent significant capacity gains without capital investment.
Machines can be running but still losing OEE through speed losses (running slower than ideal cycle time) and quality losses (producing defects). Performance and Quality scores often surprise plant managers because these losses are less visible than full stops. Track micro-stops under 2 minutes — they're often the largest hidden OEE drain [3].
Start with per-machine OEE for your bottleneck equipment. That's where improvements translate directly into throughput gains. Line-level OEE is useful for capacity planning but can mask individual machine problems. Once you've improved the bottleneck, move to the next constraint.
Measure OEE every shift at minimum. Real-time OEE tracking (updated every few minutes) is where the real gains come — operators can see losses as they happen and act on them. Shift-end summaries are a lagging indicator; real-time dashboards are leading ones.
OEE uses planned production time as the denominator, so it measures effectiveness during scheduled hours. TEEP (Total Effective Equipment Performance) uses total calendar time (24/7/365), measuring the gap between current output and theoretical maximum. TEEP is useful for capital investment decisions; OEE is better for operational improvement.

Related Resources

Sources

  1. Nakajima, S. — Introduction to TPM: Total Productive Maintenance (Productivity Press)
  2. Vorne Industries — The Complete Guide to OEE
  3. ISA / Plant Engineering — Hidden Losses: Micro-Stops and Speed Losses in Manufacturing
  4. SMRP — Best Practices for OEE Measurement and Improvement
  5. McKinsey & Company — Manufacturing OEE Improvement: Capturing Hidden Capacity

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