What is OEE (Overall Equipment Effectiveness)?
Definition, calculation method and practical tips
What is OEE?
OEE (Overall Equipment Effectiveness), known in French as TRS, is a performance indicator developed by Seiichi Nakajima in the 1960s. It measures how effectively an industrial asset is used. Today OEE is the most widely used indicator for evaluating equipment performance.
Although there is no single international consensus, OEE is essential for identifying improvement opportunities in the manufacturing process. In France it is standardised by AFNOR (NF E60-182).
OEE improvement is measured against each asset's own reference, so values are not directly comparable between different equipment types or sites. Maximising OEE, or TEEP, does not on its own guarantee the overall optimisation of the production unit.
Calculating OEE: methodology and formulas
OEE is built on three main components, combined into a single composite score.
Availability
The percentage of time the equipment is available to produce. Actual run time divided by total planned time, multiplied by 100.
Performance
How efficient the equipment is versus its maximum capacity. Actual output divided by theoretical maximum output, multiplied by 100.
Quality
The percentage of products meeting quality specifications. Good products divided by total products made, multiplied by 100.
Overall OEE
A composite measure combining availability, performance and quality into a single indication of equipment performance.
How OEE differs from related indicators
OEE vs TRG: what is the difference?
OEE measures overall effectiveness through availability, performance and quality. TRG (overall yield rate) also includes changeover and setup losses, giving a broader view. TRG often looks stricter than OEE because it factors in more elements.
Why OEE matters
OEE provides a direct measure of equipment effectiveness and a solid basis for continuous improvement. Compared with metrics that focus on isolated aspects, it gives a global view of the three key components for optimising manufacturing and cutting costs.
Setting up and tracking OEE
Using an MES to optimise OEE
An MES automatically collects the data needed to calculate OEE and provides real-time insight to quickly correct inefficiencies. Advanced reporting supports constant monitoring and continuous improvement.
Indicators and causes of performance loss
TEEPTRAK tracks and analyses equipment performance in real time, with operators logging the causes of deviation directly on a tablet.
Performance-loss nomenclature for OEE / TEEP
For effective tracking, categories such as plant shutdowns and planned downtime are usually excluded from OEE, to focus on avoidable losses.
Time breakdown: from total time to valuable time
Indicator categories and loss causes by level
Improving OEE: strategy and techniques
TPM
Total Productive Maintenance involves everyone in reducing losses: fewer unplanned stops through preventive maintenance, better quality and higher productivity from well-maintained machines.
SMED
SMED reduces changeover time: less downtime, greater flexibility for fluctuating demand and better use of resources.
Industry 4.0 integration
IoT, AI and cyber-physical systems enable real-time monitoring, advanced data analysis and more automation to calculate and improve OEE.
Want to go deeper on OEE?
Get our OEE white paperCase studies and recent analysis
Automotive components: a TPM programme lifted OEE from 65% to 85% in one year, with no extra equipment investment.
Medical devices: SMED cut changeover time from 50 to 15 minutes, raising OEE from 72% to 90%.
Beverages: real-time Industry 4.0 monitoring in a brewery improved OEE by 10 points through smarter processes.
Calculate your OEE in real time
Enter your own figures and watch availability, performance and quality combine into a live OEE score.
Real-time OEE calculator
Estimate your line’s true performance. OEE = Availability × Performance × Quality.
Scheduled production time over the period (excluding planned breaks).
min
Total unplanned stops (breakdowns, changeovers, micro-stops).
min
Theoretical time to produce one part at full speed.
s/part
All parts made, good and bad.
parts
Non-conforming parts (scrap, rework counted as defects).
parts
Measure OEE automatically, in real time, on your machines.
Key points and tips
OEE is a fundamental indicator for measuring and optimising industrial equipment performance. By combining availability, performance and quality, it gives a precise overview of production efficiency. TPM, SMED and Industry 4.0 deliver concrete gains in productivity and cost.
For production managers, quality engineers and consultants, the rigorous application of OEE principles is essential: set up continuous tracking, use modern tools such as an MES, and stay at the leading edge of innovation. OEE is not just a number to hit, but a continuous journey toward operational excellence.
Your factory in real time
See how TEEPTRAK measures and improves OEE on your shop floor. Start a free 60-day pilot.