Overall Equipment Effectiveness (OEE)
OEE is a metric for measuring productivity especially in a manufacturing setup. It identifies the percentage of manufacturing time that is actually utilized for productivite work.
Where:
- Availability = Run Time / Planned Production Time
- Performance = (Total Parts × Ideal Cycle Time) / Run Time
- Quality = Good Parts / Total Parts
OEE Calculator
Results
Overall Equipment Effectiveness:
Availability
Run Time: minutes
Performance
Theoretical Production: parts
Quality
Rejection Rate:
Loss Analysis
| Loss Category | Time Lost (minutes) | Percentage |
|---|---|---|
| Availability Loss (Downtime) | ||
| Performance Loss (Speed) | ||
| Quality Loss (Defects) | ||
| Total Productive Time |
How to Use The OEE Calculator
Our OEE calculator simplifies the OEE calculation process. Follow these steps to calculate your Overall Equipment Effectiveness:
- Enter Time Metrics: Input your planned production time (in minutes) and any downtime that occurred during this period.
- Enter Production Metrics: Provide the ideal cycle time (seconds per part) and the total number of parts produced.
- Enter Quality Metrics: Input either the number of good parts or rejected parts (the calculator will automatically compute the other value).
- Calculate: Click the "Calculate OEE" button to see your results.
What is OEE?
Overall Equipment Effectiveness (OEE) is a key metric used to measure manufacturing productivity. It shows how efficiently equipment is used compared to its maximum potential during planned production time. In simple terms, it reflects the percentage of productive manufacturing time.
OEE is calculated by multiplying three factors:
- Availability - The percentage of production time that the equipment is available to operate
- Performance - The speed at which the equipment runs as a percentage of its designed cycle time (Takt time)
- Quality - The percentage of good quality parts/products produced out of the total parts/products produced
A perfect score of 100% means flawless production: only good parts, running at maximum speed, with zero downtime.
Source: Automotive Industry Action Group (AIAG). (2010). Measurement Systems Analysis (MSA) Manual.
OEE Analysis and Improvement Strategies
Effective OEE analysis goes beyond just calculating the number. It involves understanding the root causes of losses and implementing targeted improvements:
Addressing Availability Losses
- Implement preventive maintenance schedules
- Reduce changeover times using SMED (Single-Minute Exchange of Die) techniques
- Address equipment failures through root cause analysis
Improving Performance Efficiency
- Identify and eliminate minor stops and idling
- Optimize machine settings for maximum speed while maintaining quality
- Address material flow issues that cause production delays
Enhancing Quality Rate
- Implement error-proofing (poka-yoke) devices
- Improve operator training on quality standards
- Establish robust quality control processes
Regular OEE analysis helps identify trends and prioritize improvement efforts where they will have the greatest impact on overall equipment effectiveness.
Source: Hansen, R. C. (2002). Overall Equipment Effectiveness: A Powerful Production/Maintenance Tool for Increased Profits. Industrial Press.
OEE Calculation Examples
Example 1: Basic OEE Calculation
A manufacturing cell operates with the following metrics:
- Planned Production Time: 480 minutes (8-hour shift)
- Downtime: 47 minutes
- Ideal Cycle Time: 1.0 seconds per part
- Total Parts Produced: 19,271 parts
- Good Parts: 18,847 parts
Calculations:
- Run Time = 480 - 47 = 433 minutes
- Availability = 433 / 480 = 0.9021 (90.21%)
- Performance = (19,271 × 1.0) / (433 × 60) = 19,271 / 25,980 = 0.7417 (74.17%)
- Quality = 18,847 / 19,271 = 0.9780 (97.80%)
- OEE = 0.9021 × 0.7417 × 0.9780 = 0.6545 (65.45%)
Example 2: World-Class OEE
A high-performing manufacturing line:
- Planned Production Time: 1,440 minutes (24 hours)
- Downtime: 36 minutes
- Ideal Cycle Time: 2.5 seconds per part
- Total Parts Produced: 33,200 parts
- Good Parts: 33,100 parts
Calculations:
- Run Time = 1,440 - 36 = 1,404 minutes
- Availability = 1,404 / 1,440 = 0.9750 (97.50%)
- Performance = (33,200 × 2.5) / (1,404 × 60) = 83,000 / 84,240 = 0.9853 (98.53%)
- Quality = 33,100 / 33,200 = 0.9970 (99.70%)
- OEE = 0.9750 × 0.9853 × 0.9970 = 0.9581 (95.81%)
Frequently Asked Questions About OEE
What is a good OEE score? +
OEE benchmarks vary by industry, but generally:
- 100%: Perfect production (only theoretically possible)
- 85%: World-class level (often considered the goal for discrete manufacturers)
- 60%: Normal range for many manufacturers, indicating room for more improvement
- 40%: Low score, indicating significant improvement opportunities
It's important to note that process industries (like chemicals or pharmaceuticals) often have higher OEE scores than discrete manufacturing due to the continuous nature of their processes.
How is OEE different from efficiency? +
While efficiency typically measures output against a single standard, OEE provides a more comprehensive view by measuring three distinct components of manufacturing performance:
- Availability measures uptime versus planned production time
- Performance measures actual speed versus ideal speed
- Quality measures good parts versus total parts produced
This multi-dimensional approach makes OEE a more powerful metric for identifying specific areas for improvement in manufacturing operations.
What are the Six Big Losses in OEE? +
The Six Big Losses categorize equipment productivity losses that affect OEE:
- Breakdowns (Availability Loss) - Equipment failures
- Setup and Adjustments (Availability Loss) - Changeover time
- Small Stops (Performance Loss) - Minor interruptions (< 5 minutes)
- Reduced Speed (Performance Loss) - Operating below ideal cycle time
- Startup Rejects (Quality Loss) - Defects during warm-up or startup
- Production Rejects (Quality Loss) - Defects during stable production
Identifying and addressing these Six Big Losses is fundamental to improving OEE.
Source: Nakajima, S. (1988). Introduction to TPM. Productivity Press.
How often should I measure OEE? +
The frequency of OEE measurement depends on your production process and improvement goals:
- Daily: For high-volume processes or when implementing rapid improvement initiatives
- Weekly: Common frequency for tracking overall performance trends
- Per shift: Useful for identifying shift-specific issues
- Per production run: Helpful for job-based manufacturing
More frequent measurement allows for quicker problem identification and resolution, but requires more robust data collection systems.
Can OEE be greater than 100%? +
No, OEE cannot legitimately exceed 100%. Each component of OEE is capped at 100%:
- Availability cannot exceed 100% (you can't have more time available than planned)
- Performance cannot exceed 100% (you can't run faster than the ideal cycle time)
- Quality cannot exceed 100% (you can't produce more good parts than total parts)
If you calculate an OEE greater than 100%, it typically indicates that your "ideal cycle time" is set incorrectly (too slow) or there are errors in your data collection.
Key OEE Terms and Definitions
Term
Definition
Calculation
OEE (Overall Equipment Effectiveness)
A comprehensive measure of manufacturing productivity that combines availability, performance, and quality metrics
Availability × Performance × Quality
Availability
The percentage of scheduled time that the equipment is available to operate
Run Time / Planned Production Time
Performance
The speed at which the equipment runs compared to its designed speed
(Total Parts × Ideal Cycle Time) / Run Time
Quality
The percentage of good parts out of the total parts produced
Good Parts / Total Parts
Planned Production Time
The total time scheduled for equipment operation
Total Time - Planned Shutdowns
Run Time
The time equipment was actually running
Planned Production Time - Downtime
Ideal Cycle Time
The theoretical minimum time required to produce one part
Based on equipment specifications under optimal conditions
Recommended Readings
Nakajima, S. (1988).
Introduction to TPM: Total Productive Maintenance. Productivity Press.
Hansen, R. C. (2002).
Overall Equipment Effectiveness: A Powerful Production/Maintenance Tool for Increased Profits. Industrial Press.
Wireman, T. (2005).
Total Productive Maintenance. Industrial Press.
Productivity Press Development Team. (1996).
Quick Changeover for Operators: The SMED System. Productivity Press.
Disclosure: As an Amazon Associate I earn from qualifying purchases. These links are provided for your convenience and help support this site.
Overall Equipment Effectiveness (OEE) is a key metric used to measure manufacturing productivity. It shows how efficiently equipment is used compared to its maximum potential during planned production time. In simple terms, it reflects the percentage of productive manufacturing time.
OEE is calculated by multiplying three factors:
- Availability - The percentage of production time that the equipment is available to operate
- Performance - The speed at which the equipment runs as a percentage of its designed cycle time (Takt time)
- Quality - The percentage of good quality parts/products produced out of the total parts/products produced
A perfect score of 100% means flawless production: only good parts, running at maximum speed, with zero downtime.
Source: Automotive Industry Action Group (AIAG). (2010). Measurement Systems Analysis (MSA) Manual.
OEE Analysis and Improvement Strategies
Effective OEE analysis goes beyond just calculating the number. It involves understanding the root causes of losses and implementing targeted improvements:
Addressing Availability Losses
- Implement preventive maintenance schedules
- Reduce changeover times using SMED (Single-Minute Exchange of Die) techniques
- Address equipment failures through root cause analysis
Improving Performance Efficiency
- Identify and eliminate minor stops and idling
- Optimize machine settings for maximum speed while maintaining quality
- Address material flow issues that cause production delays
Enhancing Quality Rate
- Implement error-proofing (poka-yoke) devices
- Improve operator training on quality standards
- Establish robust quality control processes
Regular OEE analysis helps identify trends and prioritize improvement efforts where they will have the greatest impact on overall equipment effectiveness.
Source: Hansen, R. C. (2002). Overall Equipment Effectiveness: A Powerful Production/Maintenance Tool for Increased Profits. Industrial Press.
OEE Calculation Examples
Example 1: Basic OEE Calculation
A manufacturing cell operates with the following metrics:
- Planned Production Time: 480 minutes (8-hour shift)
- Downtime: 47 minutes
- Ideal Cycle Time: 1.0 seconds per part
- Total Parts Produced: 19,271 parts
- Good Parts: 18,847 parts
Calculations:
- Run Time = 480 - 47 = 433 minutes
- Availability = 433 / 480 = 0.9021 (90.21%)
- Performance = (19,271 × 1.0) / (433 × 60) = 19,271 / 25,980 = 0.7417 (74.17%)
- Quality = 18,847 / 19,271 = 0.9780 (97.80%)
- OEE = 0.9021 × 0.7417 × 0.9780 = 0.6545 (65.45%)
Example 2: World-Class OEE
A high-performing manufacturing line:
- Planned Production Time: 1,440 minutes (24 hours)
- Downtime: 36 minutes
- Ideal Cycle Time: 2.5 seconds per part
- Total Parts Produced: 33,200 parts
- Good Parts: 33,100 parts
Calculations:
- Run Time = 1,440 - 36 = 1,404 minutes
- Availability = 1,404 / 1,440 = 0.9750 (97.50%)
- Performance = (33,200 × 2.5) / (1,404 × 60) = 83,000 / 84,240 = 0.9853 (98.53%)
- Quality = 33,100 / 33,200 = 0.9970 (99.70%)
- OEE = 0.9750 × 0.9853 × 0.9970 = 0.9581 (95.81%)
Frequently Asked Questions About OEE
OEE benchmarks vary by industry, but generally:
- 100%: Perfect production (only theoretically possible)
- 85%: World-class level (often considered the goal for discrete manufacturers)
- 60%: Normal range for many manufacturers, indicating room for more improvement
- 40%: Low score, indicating significant improvement opportunities
It's important to note that process industries (like chemicals or pharmaceuticals) often have higher OEE scores than discrete manufacturing due to the continuous nature of their processes.
While efficiency typically measures output against a single standard, OEE provides a more comprehensive view by measuring three distinct components of manufacturing performance:
- Availability measures uptime versus planned production time
- Performance measures actual speed versus ideal speed
- Quality measures good parts versus total parts produced
This multi-dimensional approach makes OEE a more powerful metric for identifying specific areas for improvement in manufacturing operations.
The Six Big Losses categorize equipment productivity losses that affect OEE:
- Breakdowns (Availability Loss) - Equipment failures
- Setup and Adjustments (Availability Loss) - Changeover time
- Small Stops (Performance Loss) - Minor interruptions (< 5 minutes)
- Reduced Speed (Performance Loss) - Operating below ideal cycle time
- Startup Rejects (Quality Loss) - Defects during warm-up or startup
- Production Rejects (Quality Loss) - Defects during stable production
Identifying and addressing these Six Big Losses is fundamental to improving OEE.
Source: Nakajima, S. (1988). Introduction to TPM. Productivity Press.
The frequency of OEE measurement depends on your production process and improvement goals:
- Daily: For high-volume processes or when implementing rapid improvement initiatives
- Weekly: Common frequency for tracking overall performance trends
- Per shift: Useful for identifying shift-specific issues
- Per production run: Helpful for job-based manufacturing
More frequent measurement allows for quicker problem identification and resolution, but requires more robust data collection systems.
No, OEE cannot legitimately exceed 100%. Each component of OEE is capped at 100%:
- Availability cannot exceed 100% (you can't have more time available than planned)
- Performance cannot exceed 100% (you can't run faster than the ideal cycle time)
- Quality cannot exceed 100% (you can't produce more good parts than total parts)
If you calculate an OEE greater than 100%, it typically indicates that your "ideal cycle time" is set incorrectly (too slow) or there are errors in your data collection.
Key OEE Terms and Definitions
Term
Definition
Calculation
OEE (Overall Equipment Effectiveness)
A comprehensive measure of manufacturing productivity that combines availability, performance, and quality metrics
Availability × Performance × Quality
Availability
The percentage of scheduled time that the equipment is available to operate
Run Time / Planned Production Time
Performance
The speed at which the equipment runs compared to its designed speed
(Total Parts × Ideal Cycle Time) / Run Time
Quality
The percentage of good parts out of the total parts produced
Good Parts / Total Parts
Planned Production Time
The total time scheduled for equipment operation
Total Time - Planned Shutdowns
Run Time
The time equipment was actually running
Planned Production Time - Downtime
Ideal Cycle Time
The theoretical minimum time required to produce one part
Based on equipment specifications under optimal conditions
| Term | Definition | Calculation |
|---|---|---|
| OEE (Overall Equipment Effectiveness) | A comprehensive measure of manufacturing productivity that combines availability, performance, and quality metrics | Availability × Performance × Quality |
| Availability | The percentage of scheduled time that the equipment is available to operate | Run Time / Planned Production Time |
| Performance | The speed at which the equipment runs compared to its designed speed | (Total Parts × Ideal Cycle Time) / Run Time |
| Quality | The percentage of good parts out of the total parts produced | Good Parts / Total Parts |
| Planned Production Time | The total time scheduled for equipment operation | Total Time - Planned Shutdowns |
| Run Time | The time equipment was actually running | Planned Production Time - Downtime |
| Ideal Cycle Time | The theoretical minimum time required to produce one part | Based on equipment specifications under optimal conditions |
Recommended Readings
Disclosure: As an Amazon Associate I earn from qualifying purchases. These links are provided for your convenience and help support this site.