The OEE calculation is a metric that gives us daily 
information about how effectively the machine is running 
and which of the six big losses we need to improve. Overall 
equipment effectiveness is not the only indicator to assess 
a production system, but it is certainly very important if 
our goal is improvement.

THE ELEMENTS OF OVERALL EQUIPMENT EFFECTIVENESS
The three main categories of equipment-related losses—
downtime, speed loss, and defect or quality loss—are also 
the main ingredients for determining the overall equipment 
effectiveness. Overall equipment effectiveness is 
calculated by combining three factors that reflect these 
losses: the availability rate, the performance rate, and 
the quality rate.

Overall Equipment Effectiveness is based on 3 factors

1. Availability rate
2. Performance rate
3. Quality rate

(Some companies use usability rate also)

1. Availability rate for machine - Total running time 
divided by total hours available
2. Performance rate - Total number of componants produced 
divided by total number of componants that is supposed to 
be produced
3. Quality rate - total number of quality products produced 
divided by total number of products produced
4. usability rate - total hours machine has run divided by 
total hours available (Usability talks about usage of order 
for that machine)

OEE - Availability rate x performance rate x quality rate