Maintenance · Updated 3 October 2026
OEE calculation: check availability, performance and quality
Prepare consistent production-time and count data, calculate the three OEE factors and investigate results above 100 percent.
Define the planned production period
OEE combines three factors: availability, performance and quality. Calculate all three for the same equipment and time window. Agree which time was intended for production before collecting stop durations. Keep the policy consistent between shifts.
Availability = run time ÷ planned production time. Performance = ideal cycle time × total count ÷ run time. Quality = good count ÷ total count. Multiply the decimal factors to obtain OEE, then multiply by 100 for a percentage.
Keep time and counting units aligned
- Convert cycle time and run time to the same time unit.
- Define whether a count means one product, one pack or one machine cycle.
- Use the same count unit for ideal cycle time, total count and good count.
- Reconcile counters after resets, product changes and shift handovers.
Keep original readings and any adjustments in the production record. If an HMI counter is known to double count, investigate that source before treating the resulting OEE as reliable.
Investigate performance above 100%
A performance result above 100% calls for a review of ideal cycle time, count units and run time. Do not silently cap it at 100% and keep reporting. The calculator accepts factor inputs from 0% to 100%; correct the underlying definition before entering them.
Read the three factors alongside the total
A combined score can hide a change in the type of loss. Retain availability, performance and quality in the shift record, then relate the losses to stop reasons, speed restrictions and rejects. OEE and inherent reliability availability use different time definitions, so they should not be substituted for one another.