OEE calculator
Enter the planned time, the stoppages, the ideal speed and the shift's pieces: it gives you availability, performance, quality, the OEE and how many minutes are lost in each factor.
Availability
88.8%
Performance
86.1%
Quality
97.8%
OEE
74.8%
Shift minutes lost in each factor (out of 420 planned):
- Availability (stoppages)47.0 min
- Performance (speed and micro-stops)51.8 min
- Quality (rejects)7.0 min
Where most minutes are lost: performance (speed and micro-stops). Vorne takes 85% as the world-class benchmark in discrete manufacturing (90% availability, 95% performance and 99.9% quality), but notes that it is not necessarily your target. The preloaded values are Vorne's worked example: an 8-hour shift with 60 min of breaks (420 min planned), 47 min of downtime, 60 pieces per minute, 19,271 pieces and 423 rejects, which gives 74.79%.
How it works
You enter the planned production time, the minutes of unplanned downtime, the ideal speed (pieces per minute), the total pieces and the rejected ones. The formulas are Vorne's:
- Availability = run time ÷ planned time, with run time = planned − stoppages.
- Performance = (total pieces ÷ run time) ÷ ideal speed.
- Quality = good pieces ÷ total pieces.
- OEE = availability × performance × quality. It is the same as good pieces × ideal cycle time ÷ planned time.
Below the result, the calculator converts each factor into shift minutes lost: stoppages (availability), the difference between the run time and the time that would have been needed at ideal speed (performance) and the rejected pieces at ideal speed (quality). Those three values, plus the fully productive time, add up to the planned time.
If performance comes out above 100%, the ideal speed is underestimated or the pieces were entered wrongly: check those figures before trusting the OEE. The 85% mentioned as a reference is Vorne's for discrete manufacturing, and the same guide notes that it is not necessarily your target. Regarding planned time, the guide recommends including breaks and changeovers, while its example spreadsheet subtracts the breaks: what matters is to choose one criterion and stick to it.
Sources
These are the ones from the article where the theory behind this tool is developed.
What does each factor measure and what are the Six Big Losses? It is in the article OEE: what it is and how it is calculated. The spreadsheet for tracking it shift by shift is among the Excel spreadsheets.