OEE Calculator
Overall equipment effectiveness OEE = availability × performance × quality from planned production time, downtime, ideal cycle time, total count and good count, with each factor, the scrap rate and where the lost time went.
Result…
How it's calculated
Run time = planned production time − stop time Availability = run time ÷ planned production time Performance = ideal cycle time × total count ÷ run time Quality = good count ÷ total count OEE = availability × performance × quality = good count × ideal cycle time ÷ planned production time
Overall equipment effectiveness measures how much of the planned production time made good parts at full speed. Availability counts the time lost to stops, performance the time lost to running slower than the ideal cycle time, and quality the parts that were scrapped or reworked. Multiplied together they give OEE, which equals the good count times the ideal cycle time divided by the planned time. The definitions follow OEE.com, which also notes that 85% is often called world-class (90% availability, 95% performance, 99% quality) while many plants score far lower. The scrap rate is 100% minus quality.
Your numbers, step by step
About the OEE calculator
This OEE calculator measures overall equipment effectiveness for a machine, line or cell over a shift or any period. Enter the planned production time, the time it was stopped, the ideal cycle time (or the ideal run rate), the total parts made and the good parts, and it returns OEE with its three factors: availability, performance and quality. It also gives the scrap and rework rate, the fully productive time, and splits the lost time into stops, slow running and rejects, so you can see which loss is the biggest and where to start. Production managers, maintenance teams and students use it to track a line from week to week. The steps show every ratio with your own numbers, and it flags a performance above 100%, which means the ideal cycle time is set too slow.
How to use it
- Choose the “Time unit” and enter the “Planned production time” and the “Stop time (downtime)”.
- Pick “Ideal speed as” an “Ideal cycle time” in seconds per part or an “Ideal run rate” in parts per minute.
- Enter the “Total count” of parts made and the “Good count” that passed first time.
- Read OEE, then availability, performance and quality to see which factor pulls it down.
- Use the lost-time split in the working to choose what to improve first.
Worked example
A 420-minute shift with 47 minutes of stops runs for 373 minutes: availability = 373 ÷ 420 = 88.8%. At an ideal cycle time of 1 s, 19,271 parts need 19,271 s against 22,380 s of run time: performance = 86.1%. With 18,848 good parts, quality = 97.8%. OEE = 88.8% × 86.1% × 97.8% = 74.8%, and the scrap and rework rate is 2.2%.
Updated
Questions people ask
How do I calculate OEE?
OEE = availability × performance × quality. Availability is run time ÷ planned production time, performance is ideal cycle time × total count ÷ run time, and quality is good count ÷ total count, as defined by OEE.com.
What is the shortcut formula for OEE?
OEE = good count × ideal cycle time ÷ planned production time. It gives the same answer as multiplying the three factors, and the working shows both.
What is a good OEE score?
OEE.com says 85% is often called world-class, based on 90% availability, 95% performance and 99% quality, and that many plants score nearer 60%. A fair target depends on your process, so track your own trend.
Why is my performance over 100%?
The ideal cycle time you entered is slower than the machine really ran, or a count or time is wrong. Use the fastest cycle the process can achieve, not a standard rate with allowances built in.
Should changeovers count as downtime?
In the OEE.com definition, stop time includes planned stops such as changeovers as well as breakdowns. Some sites leave planned stops out; pick one rule and keep it so figures compare. For other percentage checks use the percentage calculator.
What does an OEE figure not tell me?
It shows how well planned time was used, not whether the plan, staffing or demand were right, and it hides the reasons behind each loss. Pair it with a log of stop reasons and reject causes.