How to Calculate OEE: Formula & Example

OEE (Overall Equipment Effectiveness) tells you how much of your planned production time is genuinely productive: making good parts, at full speed, with no stops. You calculate it by multiplying three factors, each between 0 and 100 percent.

The OEE formula

OEE = Availability × Performance × Quality

Step by step

Find Availability. Availability = Run Time / Planned Production Time, where Run Time is planned time minus every stop (breakdowns, changeovers and small stops).
Find Performance. Performance = (Ideal Cycle Time × Total Count) / Run Time. This captures speed loss and short stops, running slower than the nameplate rate.
Find Quality. Quality = Good Count / Total Count. Rework counts as a defect, because it was not right first time.
Multiply the three factors. Multiply Availability × Performance × Quality to get OEE as a single percentage.

A worked example

Take an 8-hour shift (480 minutes) with 60 minutes of stops, an ideal cycle time of 1 second, 22,000 pieces produced and 500 rejects:

Step	Calculation	Result
Availability	420 / 480	87.5%
Performance	(1 × 22,000) / 25,200s	87.3%
Quality	21,500 / 22,000	97.7%
OEE	.875 × .873 × .977	74.7%

Skip the spreadsheet

Our free OEE Calculator does this live, with the benchmark overlay.

Open the OEE Calculator

Common mistakes

Leaving small stops and speed loss out, which inflates the number.
Counting reworked parts as good (they are defects for OEE).
Mixing up planned production time with all calendar time (that is TEEP, not OEE).

OEE FAQ

What is a good OEE?

85 percent is the widely used world-class benchmark and around 60 percent is typical for discrete manufacturing, but compare against your own trend first, then your industry.

Is OEE the same as utilisation?

No. OEE measures productive time within planned production. Utilisation against all calendar time is closer to TEEP.

What lowers OEE the most?

Usually unlogged micro-stops and speed loss (the Performance factor), because they are hard to see by hand.