OEE calculator

Multiply availability by performance by quality. Availability is run time divided by planned production time, performance is ideal cycle time times total count divided by run time, and quality is good count divided by total count. The same result comes from one shortcut: good count times ideal cycle time, divided by planned production time.

Planned stops are time the machine was never meant to run, such as breaks, team meetings or no orders; they are taken out before OEE is measured. Downtime is time the machine was meant to run but did not, such as breakdowns, changeovers and waiting for material; it lowers availability.

Ideal cycle time is the fastest time the machine or line can make one unit under ideal conditions, often the nameplate or design rate. Using a slower 'typical' time makes performance look better than it is, and can push it above 100%.

Performance above 100% means more units were counted than the ideal cycle time allows in the run time. The ideal cycle time is usually set too slow, or the counts or run time are wrong. Set the ideal cycle time to the fastest the equipment can run.

100% OEE means only good parts, made as fast as possible, with no stop time. The 85% figure often called world-class is usually attributed to Seiichi Nakajima's work on Total Productive Maintenance (TPM). It is a reference point rather than a target for every process; the most useful comparison is your own line's OEE over time.

No. Utilization usually compares run time with all available time, and efficiency often compares output with a target. OEE combines three losses in one number: stops (availability), slow running (performance) and defects (quality), all measured against planned production time.