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OEE tells you how much real production you got out of the time you planned to run. This calculator gives you your score, breaks it into the three drivers, and tells you which one to fix first. Plug in your numbers, watch the result update live, then save the score and get a 90 day improvement roadmap.
FAQ
No. Subtract scheduled breaks from your planned production time before you put anything in the calculator. Stop time should only include unplanned events: breakdowns, changeovers, material shortages, waiting on operators or supervisors. Counting breaks as downtime makes Availability look artificially low and hides the real losses.
A rework still counts as a reject. OEE measures first-pass quality. If it took an extra step beyond the standard cycle to make the part good, it is a quality loss, even if it eventually ships. The exception is if you have already counted the rework time inside Stop time, in which case it would double-count.
The machine spec sheet or OEM documentation. If you cannot find it there, time the actual best-case cycle on the floor with no operator interruption, no quality issues, no setup events. Use that as your standard. Do not use the average; that hides Performance loss.
For a small or mid-size manufacturer, 40 percent is typical of a plant that does not actively manage equipment. 60 percent is average once basic tracking is in place. 85 percent is world class and is rare outside high-volume, high-discipline operations. Most plants we work with land between 50 and 65 percent on the constraint machine.
If Availability is the lowest, run a Pareto on your downtime reason codes and attack the top one. If Performance is lowest, validate the ideal cycle time and look for short stoppages under five minutes. If Quality is lowest, run a Pareto on reject reasons and a 5-Why on the top defect. The full walkthrough is on the Sharpen blog: How to calculate OEE: full walkthrough.
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The Sharpen platform covers the full operating system that makes a number like OEE move. The free 10-minute diagnostic scores your plant across all 10 pillars and produces a prioritized roadmap. See the methodology behind it, or take the diagnostic yourself.