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OEE calculator

OEE measures what share of planned time becomes good product at nominal speed. It multiplies three factors: availability (time the machine actually runs), performance (real speed versus nominal) and quality (share of good product).

Pre-selection and estimation tool. Check the result against the real data of your product and manufacturer.

Formulas

• OEE (%) = availability (%) × performance (%) × quality (%) ÷ 10,000
• Availability = run time ÷ planned time
• Performance = (units produced × ideal cycle time) ÷ run time
• Quality = good units ÷ units produced

Worked example

With 90 % availability, 95 % performance and 99 % quality, OEE is 0.90 × 0.95 × 0.99 = 84.6 %. That is just below the 85 % usually taken as a world-class reference: the factor with most room is availability, so stops are the first place to look.

Limits and how to use it

• The 85 % reference is indicative; what matters is measuring OEE consistently and comparing it with the line's own history.
• If a line has several machines, the OEE that matters is the bottleneck's.
• Micro-stops usually hide in performance, not in availability: it pays to log them separately.

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