Gesamtanlageneffektivität (OEE) is a manufacturing metric that shows how effectively a machine or production line runs compared with its full potential. OEE combines availability, performance and quality. It helps teams see whether output is lost through downtime, slow running or defects.
Use OEE with the loss events behind the number. A percentage alone does not explain a production problem.
How is OEE calculated?
OEE = Availability × Performance × Quality
- Verfügbarkeit compares planned production time with the time the equipment actually runs. Breakdowns, setups, changeovers and waiting reduce the result.
- Leistung compares the actual rate with the ideal cycle time or target rate. Slow cycles and short interruptions reduce performance.
- Qualität measures the share of output that meets requirements. Scrap and rework reduce quality.
Because the factors are multiplied, a weak result in one area can pull down the total OEE even when the other factors look healthy.
What losses does OEE reveal?
- Availability losses: failures, changeovers, waiting and other stops.
- Performance losses: reduced speed, minor stops and running below the ideal rate.
- Quality losses: startup rejects, defects, scrap and rework.
This breakdown helps a team move from “OEE fell” to a practical question such as “which stop reason, speed loss or defect contributed most?”
OEE example
A line has 480 minutes of planned time. It runs for 420 minutes, reaches 90% of its ideal rate and produces 95% good units. Its OEE is 87.5% × 90% × 95%, or about 74.8%.
OEE therefore differs from uptime. Uptime describes whether equipment was running. OEE also measures the rate and quality of the output.
Benefits and limitations of OEE
- creates a shared language for production losses;
- helps teams prioritise improvement work with measured evidence;
- supports comparisons when sites use the same definitions; and
- shows whether an action affected downtime, speed or quality.
OEE can mislead when teams define planned time, ideal cycle times, stop reasons or quality inconsistently. It should not become a target that encourages people to hide stops or lower the ideal rate. Use it with safety, delivery, cost and maintenance measures.
When should a manufacturer use OEE?
OEE is a useful starting point when a manufacturer needs a consistent view of line performance, wants to identify hidden losses or is prioritising continuous improvement. Agree on the calculation rules before comparing lines or sites.
For a commercial overview of automated OEE and loss analysis, see Accevo OEE and micro-stops intelligence software.