How OEE is Calculated?

Owned by Geisson Velasco
Last updated: Aug 19, 2024
3 min read

Shoplogix uses the standard OEE formula for reports. That is:

OEE = Availability * Performance * Quality

where:

  • Availability = Uptime [Hours] / Scheduled Time [Hours]

  • Performance = OEE Runtime [Hours] / Uptime [Hours]

    • OEE Runtime [Hours] = Total Production [Parts] / Machine Rate [Parts Per Hour]

  • Quality = OEE Productive [Hours] / OEE Runtime [Hours]

    • OEE Productive [Hours] = Good Production [Parts] / Machine Rate [Parts Per Hour]

    • OEE Runtime [Hours] = Total Production [Parts] / Machine Rate [Parts Per Hour]

 

Let’s consider Job-A and Job-B as an example:

Job

Machine Rate* [Parts Per Hour]

Uptime [Hours]

Scheduled Time [Hours]

Total Production [Parts]

Good Production [Parts]

Job

Machine Rate* [Parts Per Hour]

Uptime [Hours]

Scheduled Time [Hours]

Total Production [Parts]

Good Production [Parts]

Job-A

100

1.00

1.00

70

50

Job-B

1000

0.25

0.25

250

250

If there is a job, the machine rate is equal to the Job Maximum Run Rate; otherwise, it is equal to the Expected Production Rate.

Let's calculate the OEE of Job-A.

OEE = Availability * Performance * Quality

  • Availability = Uptime [Hours] / Scheduled Time [Hours]
    = 1 hour / 1 hour = 1.00

  • Performance = OEE Runtime [Hours] / Uptime [Hours]

    • OEE Runtime [Hours] = Total Production [Parts] / Machine Rate [Parts Per Hour]
      =70 parts / 100 parts per hour = 0.7 hours

So, Performance = OEE Runtime [Hours] / Uptime [Hours] = 0.7 hours / 1.00 hours = 0.7

  • Quality = OEE Productive [Hours] / OEE Runtime [Hours]

    • OEE Productive [Hours] = Good Production [Parts] / Machine Rate [Parts Per Hour]
      = 50 parts / 100 parts per hour = 0.5 hours

    • OEE Runtime [Hours] = Total Production [Parts] / Machine Rate [Parts Per Hour]
      = 70 parts / 100 parts per hour = 0.7 hours

So, Quality = OEE Productive [Hours] / OEE Runtime [Hours] = 0.5 hours / 0.7 hours = 0.714

Therefore, OEE = Availability * Performance * Quality = 1.00 x 0.7 x 0.714 = 0.5 or 50%

 

Similarly, we can calculate the OEE of Job-B:

OEE = Availability * Performance * Quality

  • Availability = 1.00

  • Performance = 1.00

  • Quality = 1.00

Therefore, OEE = Availability * Performance * Quality = 1.00 or 100%

 

However, if you want to calculate the OEE for the entire time both jobs ran, a weighted average based on duration is used for calculating OEE. Essentially, the job with the greatest duration would have more influence on the overall OEE.

That is:

OEE Overall = (OEE Job-1 * OEE Duration Weight Job-1) + (OEE Job-2 * OEE Duration Weight Job-2) + … + (OEE Job-n x OEE Duration Weight Job-n)

The OEE Scheduled Duration Weight is calculated as follows:

OEE Duration Weight = Duration Scheduled Time of Job [Hours] / Total Scheduled Time of All Jobs [Hours]

The uptime of Job-A is 1.00 hours.
The uptime of Job-B is 0.25 hours.
The total uptime is the sum of all job uptimes, amounting to 1.25 hours.

So,

  • OEE Duration Weight Job-A = 1.00 hours/ 1.25 hours = 0.8

  • OEE Duration Weight Job-B = 0.25 hours/ 1.25 hours = 0.2

Hence,

OEE Overall = (OEE Job-A * OEE Duration Weight Job-1) + (OEE Job-B * OEE Duration Weight Job-B)
OEE Overall = (0.5 * O.8) + (1.00 x 0.2) = 0.6

Therefore, the OEE Overall for the entire time of both jobs Job-A and Job-B is 0.6 or 60%

Note that OEE Average = (OEE Job-A + OEE Job-B) / 2 = 0.75 does not weight based on the job that had the most scheduled time. This is for comparison only, as it is not used in Shoplogix standard reports.