How is it calculated?
- Availability = (planned time − downtime) ÷ planned time
- Performance = (ideal cycle time × units produced) ÷ run time
- Quality = (produced − defective) ÷ produced
- OEE = availability × performance × quality. It shows how much of the maximum output possible in the planned time came out as good parts.
Calculating OEE once is the easy part. The benefit comes when it's measured every day for every machine and downtime is recorded with its causes. Downtime written on paper or in Excel at the end of the day is both incomplete and late. When the operator picks the stoppage on a tablet as it happens, you can see straight away how many hours a month each breakdown, each mould or each wait for materials costs you. More on this in the production management software article.
Frequently asked questions
What is a good OEE?
Around 85% is considered world class. In companies that have just started measuring, 40–60% is common. What matters more than the figure itself is which of the three components the loss is concentrated in, and how it changes from week to week.
Where do I find the ideal cycle time?
The time it takes the machine or mould to produce one part when nothing goes wrong. Use the value in the machine's specifications or the best sustained speed you've seen. If performance comes out above 100%, the cycle time you entered is too long.
Are breaks included in planned time?
No. Subtract from the shift time anything you already know won't be worked, such as lunch, tea breaks and planned maintenance. Breakdowns, setups, mould changes and waiting for materials are entered as downtime.
Are the numbers I enter sent anywhere?
Not unless you send them. The calculation is done entirely in your browser and nothing is saved. Your figures reach us only if you fill in and send the “Evaluate my result” form, so that we can get back to you.