About the OEE Calculator
Overall equipment effectiveness (OEE) is the standard measure of how productive a machine or production line really is compared with its theoretical maximum. It multiplies three factors: availability (the share of planned time the equipment was actually running), performance (how fast it ran compared with its ideal cycle time) and quality (the share of parts that were good first time).
Enter the shift length, planned breaks, unplanned downtime, the ideal cycle time per part, and the total and good part counts. The calculator returns OEE and each of its three components, plus a breakdown of the planned production time into availability, speed and quality losses, so you can see which of the "six big losses" to attack first.
It is useful for plant managers, maintenance and continuous-improvement teams, and anyone running a TPM or Lean programme. Planned breaks and meetings are removed from the time base, so OEE measures losses only during time the line was scheduled to produce.
With the default inputs, the oee is 74.8%. Change any value above to recalculate instantly.
How to use the oee calculator
- 1Enter the shift length and the planned stops such as breaks and meetings.
- 2Enter unplanned downtime from breakdowns, changeovers and shortages.
- 3Enter the ideal cycle time per part in seconds.
- 4Enter the total parts produced and how many were good first time.
- 5Read OEE and use the loss table to see which factor costs the most time.
Formula and method
Availability = run time ÷ planned production time, where planned production time is the shift length minus planned stops, and run time is planned time minus unplanned downtime. Performance = (ideal cycle time × total count) ÷ run time, which captures slow cycles and short stops. Quality = good count ÷ total count.
Multiplying the three gives OEE, which equals fully productive time (ideal cycle time × good count) divided by planned production time. An OEE of 100% means only good parts, as fast as possible, with no stops. The loss table converts each factor into minutes so the availability, performance and quality losses add back up to planned time.
- Availability
- Run time ÷ planned production time
- Performance
- Ideal cycle time × total count ÷ run time
- Quality
- Good count ÷ total count
Worked examples
8-hour shift with 47 minutes of downtime
Planned time is 480 − 60 = 420 minutes and run time 420 − 47 = 373, so availability is 88.8%. At a 1-second ideal cycle, 19,271 parts take 321.2 minutes, giving 86.1% performance. 18,848 good parts out of 19,271 is 97.8% quality, and 0.888 × 0.861 × 0.978 ≈ 74.8% OEE.
Packaging line, 10-hour shift
Planned time is 555 minutes and run time 525 (94.6% availability). 11,500 parts × 2.5 s = 479.2 minutes, or 91.3% performance. Quality is 11,270 ÷ 11,500 = 98%, so OEE is about 84.6% — just short of world class.
Frequently asked questions
What is a good OEE score?+
An OEE of 85% is the most widely quoted world-class benchmark for discrete manufacturing; commonly quoted rules of thumb put typical plants nearer 60% and plants that have just started measuring nearer 40%. Compare against your own baseline rather than chasing a universal number.
How do you calculate OEE?+
Multiply availability × performance × quality. Availability is run time ÷ planned time, performance is ideal cycle time × total count ÷ run time, and quality is good count ÷ total count. Equivalently, OEE = good count × ideal cycle time ÷ planned production time.
Should breaks be included in OEE?+
No. Planned stops such as breaks, lunches and scheduled meetings are removed to get planned production time. Measuring against all calendar time is a different metric, called TEEP (total effective equipment performance).
Why is my performance over 100%?+
Performance above 100% means the ideal cycle time you entered is slower than the machine actually ran. Use the nameplate capacity or the best rate ever sustained as the ideal cycle time so performance is capped at a realistic 100%.
What are the six big losses?+
They are equipment failures and setups/adjustments (availability losses), idling/minor stops and reduced speed (performance losses), and process defects and start-up rejects (quality losses). OEE groups them into its three factors.