What Is OEE (Overall Equipment Effectiveness) — and How to Calculate It

5 min read · Updated July 2026

Overall Equipment Effectiveness (OEE) is the single best measure of how productively a piece of equipment — or a whole line — is actually running. This guide covers the formula, a worked example, and what "good" looks like.

The OEE formula

OEE multiplies three factors, each a percentage:

• Availability — is the equipment running when it should be? (accounts for breakdowns and changeovers)
• Performance — is it running at its rated speed? (accounts for slow cycles and minor stops)
• Quality — how much of the output is good first time? (accounts for defects and rework)

OEE = Availability × Performance × Quality.

A worked example

Suppose a machine is scheduled for 8 hours but runs for 6 (Availability = 75%), runs at 90% of its rated speed (Performance = 90%), and 95% of parts are good (Quality = 95%). OEE = 0.75 × 0.90 × 0.95 = 0.64, or 64%.

What is a good OEE score?

• 85%+ is considered world-class for discrete manufacturing.
• 60% is typical for many operations — with plenty of room to improve.
• 40% is common where OEE is being measured for the first time.

How to improve OEE

Because OEE is a product of three factors, the biggest gain usually comes from your weakest one. Reduce unplanned downtime and speed up changeovers to lift Availability; tackle minor stops and slow running for Performance; and cut defects and rework for Quality.