Free OEE Calculator
Calculate Overall Equipment Effectiveness using availability, performance, and quality to measure manufacturing efficiency.
When to use this calculator
Overall equipment effectiveness (OEE) combines availability, performance, and quality into one asset productivity score. Production managers and CI teams use it on constraint equipment daily or weekly. Calculate when schedule attainment looks fine but output misses plan.
Methodology and inputs
OEE = availability × performance × quality. Availability = run time ÷ planned production time; performance = actual rate ÷ ideal rate; quality = good units ÷ total units produced.
Worked example
CNC cell planned 480 minutes, ran 410 after setups (85.4% availability). Produced 1,640 at 4.2/min vs ideal 5/min (84% performance). Good parts 1,558 (95% quality). OEE = 0.854 × 0.84 × 0.95 = 68.1% — world-class is ~85%; performance loss is the largest lever.
How to interpret the result
Low OEE on a bottleneck caps plant revenue — fixing non-constraints first wastes effort. Track components separately; multiplying hides whether downtime or speed losses dominate.
Reviewed by ZBI Tools · Practical finance and operations calculators for SMB teams.
Further reading
For a deeper walkthrough of the concepts behind this tool, see our guide: Read the full analysis guide.
Related hub: Browse all calculators · Analyzers & calculators home · About Zen Box Infinity
Practical questions
Ideal cycle time source?
Use documented design speed proven on short runs — not theoretical nameplate.
Planned maintenance?
Exclude from planned production time if maintenance is scheduled — align with corporate OEE standard.
OEE on manual lines?
Yes with labor-paced ideal rates — less common but valid for assembly cells.
Formulas
OEE % = Availability × Performance × Quality
Enter each factor as a percentage (e.g. 92 for 92%).
Example: Availability 0.92; performance 0.88; quality 0.97 → OEE ≈ 78.5%.
Source: ZBI Business Control Library — oee.
FAQ
What is OEE?
OEE measures how effectively equipment converts planned time into good output. It combines availability, performance and quality.
How do you calculate OEE?
Multiply availability, performance and quality (as decimals). Example: 0.92 × 0.88 × 0.97 ≈ 78.5%.
Are my inputs saved?
No. Calculations run in your browser only.