Overall Equipment Effectiveness

Overall Equipment Effectiveness (OEE) is an operational metric used in manufacturing to quantify how effectively equipment is used to produce conforming products during scheduled production time.

OEE is calculated as the product of three factors:

• Availability: The proportion of scheduled production time during which the equipment is actually running. It accounts for unplanned stops (such as breakdowns) and planned stops (such as changeovers) within the scheduled period.
• Performance: The ratio between the actual production rate and the equipment’s ideal or specified production rate while it is running. It reflects losses such as minor stops and reduced operating speed.
• Quality: The proportion of produced units that meet defined quality standards, excluding scrap and rework from the total count of produced units.

In formula form, OEE is expressed as:

OEE = Availability × Performance × Quality

Organizations typically calculate OEE for a machine, line, cell, or area over a defined time window (for example, a shift, day, or week). The metric is used to track losses related to downtime, speed, and quality, and to compare current equipment utilization against a defined reference such as design capacity or ideal operating conditions.