OEE: Overall Equipment Effectiveness With a Worked Example
October 29, 2026
Overall equipment effectiveness (OEE) measures how much of the planned production time is truly productive. It multiplies three factors: availability (the share of planned time the machine runs), performance (actual speed versus ideal speed), and quality (good units as a share of total units). OEE = A × P × Q.
Example: a machine is scheduled for a 480-minute shift with 48 minutes of downtime for changeovers and breakdowns, so it runs 432 minutes, an availability of 90%. Its ideal speed is 60 units a minute, so in 432 minutes it could make 25,920 units. It makes 24,624, a performance of 95%. Of those, 24,132 are good, a quality of 98%. OEE = 0.90 × 0.95 × 0.98 = 83.8%.
Skip the math and get your answer instantly:
Open the Percentage Calculator →Loss Waterfall in Units
In 480 minutes at the ideal speed, the machine could make 28,800 units. OEE is the fraction that were good: 24,132 ÷ 28,800 = 83.8%. The 4,668 lost units break down into: availability loss 48 minutes × 60 = 2,880 units; performance loss 25,920 − 24,624 = 1,296 units; quality loss 24,624 − 24,132 = 492 units. The biggest lever here is downtime, then speed. Splitting the loss into these categories tells you where to focus; a single OEE number doesn't.
| Factor | Calculation | Result | Units lost |
|---|---|---|---|
| Availability | 432 / 480 | 90.0% | 2,880 |
| Performance | 24,624 / 25,920 | 95.0% | 1,296 |
| Quality | 24,132 / 24,624 | 98.0% | 492 |
| OEE | 0.90 x 0.95 x 0.98 | 83.8% | 4,668 total |
Benchmarks
An OEE of 85% is often cited as world-class for discrete manufacturing, 60% as typical, and 40% as common for companies just beginning to measure it. The right target depends on the process: continuous processes can reach higher, and high-mix operations with many changeovers lower. Compare the same machine over time, rather than different kinds of equipment. Define planned production time consistently (some exclude breaks and planned maintenance), or the figures aren't comparable.
Improving Each Factor
Availability: reduce changeover time with SMED methods, preventive maintenance, spare parts, and operator training. Performance: remove micro-stops, correct speed settings, and consistent material. Quality: tighter process control, first-piece inspection, and operator checks. Raising availability from 90% to 93% increases OEE from 83.8% to 86.6% (a gain of about 800 units a shift here). The effect is multiplicative, so small improvements in each factor add up.
Using OEE Wisely
OEE can be gamed: speeds set too low or standards that are too soft inflate it. Use the true ideal cycle time. It also doesn't take account of bottlenecks: improving a non-bottleneck machine doesn't increase plant output. Combine it with throughput and cost measures.
Frequently Asked Questions
How is OEE calculated?
Availability × performance × quality.
What is a world-class OEE?
About 85% for discrete manufacturing.
What is the performance factor?
Actual output divided by the output at ideal speed during run time.
Why separate the three losses?
To see where to focus improvements.
Does improving a non-bottleneck machine raise plant output?
Not necessarily.