Overall Equipment Effectiveness (OEE)

Everything you ever needed to know about OEE.

(Free) Maintenance Acronyms Guide

What is Overall Equipment Effectiveness (OEE)?

Overall Equipment Effectiveness (OEE) is a maintenance metric that takes availability, performance, and production quality into account to rate the productivity of assets and systems.

Manufacturers across industries calculate OEE to better understand the effectiveness of their individual assets and their production processes as a whole. The calculations compare the asset or system’s actual productivity to peak performance. 

Digging into performance data and OEE calculations can offer surprising insights. Often, the process helps to identify the root causes of unplanned downtime and other inefficiencies to ensure maintenance teams can take corrective actions.

Tracking OEE is an essential component of lean manufacturing and Total Productive Maintenance (TPM). OEE scores help lean manufacturers locate and eliminate sources of waste to maintain continuous improvement. As a maintenance KPI, Overall Equipment Effectiveness offers a performance benchmark for any organization hoping to maximize their assets’ productive time.  

Calculating OEE

The numbers you’ll need for calculating OEE fall into two main categories: parts and time. 

Measuring the number of parts you have produced involves tracking the following: 

  • Good part count: The number of good parts (parts that meet your standards for quality products without requiring scrap or rework) produced during a set period.
  • Defective part count: The number of parts produced during a set period that failed to meet quality standards.
  • Total count: The total number of parts made during a set period.

While measuring production time involves tracking theses data points: 

  • Planned production time: The total amount of time a piece of equipment or system is expected and scheduled to run.
  • Run time: The amount of time a production line or asset is actually operating as intended. Run time does not include downtime but does include small stops, brief idling, reduced speed, or time spent addressing rejected parts.
  • Stop time: the total amount of time production was stopped due to both planned downtime (changeovers, make-ready events) and unplanned stops (equipment failures, material shortages).

Availability, performance, and quality: the factors affecting OEE scores

All of those data points eventually help you understand the three factors that make up Overall Equipment Effectiveness:  

  • Availability: The amount of time your equipment is running as it should. Availability is expressed as a percentage and calculated by comparing planned operating time to actual operating time. Availability losses include all types of planned and unplanned stoppages.
  • Performance: The speed and consistency of production. Performance is represented by a percentage, comparing actual run time to ideal run time. Performance losses may be caused by small stops or slow cycles.
  • Quality: The quality of parts and frequency of defects. Quality is represented by a percentage that shows how many of the total parts you produced met quality standards. Sources of quality loss include operator error and poorly calibrated equipment. 

OEE formulas

To calculate OEE, you need to first calculate availability, performance, and quality. 

Availability = Run Time / Planned Production Time 

Performance = (Ideal Cycle Time x Total Count) / Run Time

Quality = Good Part Count / Total Count

Once you’ve calculated these three figures, you’ve got everything you need to determine OEE.

OEE = Availability x Performance x Quality

Achieving an OEE score of 100% would require producing defect-free products at maximum speed without any unplanned stoppages. As you can probably guess, even world-class organizations aren’t capable of sustaining a perfect OEE score

OEE standards vary from across industries and organizations. A common rule of thumb holds that 85% is a world-class score. What’s more important than the value itself is your team’s commitment to improvement. Once you’ve calculated OEE, you have a valuable baseline for understanding your performance and a roadmap for making changes. 

Why is OEE important?

OEE assessments empower you to make a bottom-line impact and optimize your manufacturing operations. Some benefits of improving OEE include: 

  • Increased productivity and efficiency: Calculating OEE helps identify inefficiencies in manufacturing processes to quickly introduce improvements and continually exceed customer expectations. 
  • Cost savings: Minimizing costly production delays and optimizing production quality help drive down costs. What’s more, efficient use of equipment reduces the wear and tear that leads to costly repairs and replacements. 
  • Improved capacity and throughput: Eliminating bottlenecks and using equipment more efficiently enables manufacturers to capably produce larger quantities of high-quality products without putting additional strain on their people or assets. 
  • Better decision making: All those data points enable you to make smarter, more strategic decisions. You’ll allocate resources more effectively, plan and schedule maintenance more efficiently, and think with a long-term vision in mind. 

The Six Big Losses

The ultimate goal of calculating OEE and driving continuous improvements is to address the Six Big Losses. They’re the primary drivers of inefficiency in manufacturing:

You can’t avoid these losses altogether, but improving on the performance metrics that factor into OEE can minimize their occurrence and impact.

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Best practices for improving your OEE score

Improving OEE requires a systematic approach and buy-in from across the organization. Here are some best practices for introducing OEE to your team and making ongoing improvements a reality. 

  1. Start with a pilot program: Don’t try to overhaul your entire organization all at once. Begin by picking out a production area, team, or piece of equipment as a starting point. Set a timeframe for your pilot program and make sure you’re collecting enough data. Once the pilot is complete, analyze the results and start refining your approach. 
  2. Build a strong foundation: Develop SOPs, instill good data practices, and establish a well-oiled preventive maintenance program before making OEE a foundation of your strategy.
  3. Emphasize the importance of continuous improvement: Calculating OEE is all about setting the stage for incremental improvements over time. Encourage everyone to work toward gradual improvement rather than risky quick win opportunities. 
  4. Leverage technology: Automation in the form of remote monitoring can reduce the impact of human error on production processes while reducing the burden on your maintenance team. Real-time performance insights combined with historical data can empower all sorts of improvements. Additionally, implementing a CMMS platform can offer even more benefit, centralizing key data and simplifying reporting. 

Learn more about how a CMMS can drive OEE improvements and help you reach a new standard of maintenance excellence in our guide to these powerful solutions.


Why use CMMS software to track maintenance metrics?

Using CMMS software simplifies tracking complex maintenance metrics, fosters data-driven decisions, enhancing efficiency, reducing downtime, and aiding in regulatory compliance all in one.

Is Limble Mobile CMMS app user friendly?

Limble is consistently rated Easiest-to-Use CMMS on review sites like G2, Capterra, and Software Advice. And our customers agree. With our mobile CMMS app, teams experience 30%+ better productivity, on average, requiring little to no training or ramp-up time. Our CMMS app can travel with your team, no matter where they go! Visit our App Store or Google Play for more information.

Can I connect to other systems?

Limble provides seamless, pre-built CMMS Integrations with the most widely used software systems. That means no help from a developer or your IT team is required. Learn more about our integrations.

How secure is the Limble CMMS platform?

At Limble, our world-class data security practices ensure your account information is safe. We use state-of-the-art technologies and industry best practices to maintain a secure infrastructure, including SOC-II Type II certification, regular penetration testing, and continuous security training for our staff.

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