OEE Calculator

What Is OEE (Overall Equipment Effectiveness)?

OEE is the gold-standard metric for measuring manufacturing productivity. Developed as part of Total Productive Maintenance (TPM), it combines three independent factors — Availability, Performance, and Quality — into a single percentage that reveals how much of your planned production time is truly productive.

The Three OEE Factors

Availability measures uptime: what fraction of planned time the equipment was actually running, excluding unplanned stops like breakdowns and changeovers. Performance measures speed: whether the equipment ran at its ideal cycle time or experienced slow cycles and minor stops. Quality measures yield: the proportion of parts that were good on first pass, excluding scrap and rework.

OEE = Availability × Performance × Quality. Each factor is a percentage, so even small losses in each compound into a large overall loss. For example, 90% × 90% × 90% = 72.9% OEE.

World-Class Benchmarks

The widely cited world-class benchmark is 85% OEE (90% Availability × 95% Performance × 99.9% Quality). Most discrete manufacturers operate between 55-65%. An OEE below 40% indicates major losses that represent immediate improvement opportunities — often achievable through basic TPM practices like autonomous maintenance and focused improvement (kobetsu kaizen).

The Six Big Losses

OEE losses map directly to the Six Big Losses framework in TPM: equipment failure and breakdowns (Availability), setup and adjustment (Availability), idling and minor stops (Performance), reduced speed (Performance), process defects (Quality), and reduced yield at startup (Quality). Categorizing losses this way helps teams prioritize which problems to tackle first using tools like root cause analysis and A3 problem-solving.