OEE Calculator — Availability × Performance × Quality
Planned time, downtime, ideal cycle time and the pieces made — and the overall equipment effectiveness of the machine or line.
Result
- Run time
- 420 min
- Availability
- 87.5%
- Performance
- 89.3%
- Quality
- 96.0%
- OEE
- 75.0%
720 good pieces. World-class is about 85%; the biggest loss here is downtime.
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Quick answer
OEE = Availability × Performance × Quality. Availability = run time ÷ planned production time; Performance = (ideal cycle time × total pieces) ÷ run time; Quality = good pieces ÷ total pieces. World-class OEE is about 85%; many plants start near 40–60%.
| Formula | Availability × Performance × Quality |
|---|---|
| World class | About 85% |
| Typical first measurement | 40–60% |
| Cost | Free — no sign-up, runs in your browser |
OEE — overall equipment effectiveness — measures how much of the time a machine was planned to run was turned into good parts at full speed. It multiplies three losses together: time lost to stoppages, speed lost to slow cycles and small stops, and parts lost to rejects.
Because it multiplies, three respectable-looking figures make a poor total: 90% availability × 90% performance × 95% quality is only 77% OEE. That is why OEE is useful — it shows which of the three losses is costing the most capacity.
The formula
- Run time
Planned production time − Downtime- Availability
Run time ÷ Planned production time- Performance
(Ideal cycle time × Total pieces) ÷ Run time- Quality
Good pieces ÷ Total pieces- OEE
Availability × Performance × Quality
A worked OEE calculation
A shift has 480 minutes of planned production time. The machine was down 60 minutes, so run time is 420 minutes and availability is 420 ÷ 480 = 87.5%. Ideal cycle time is 30 seconds and 750 pieces were made: 750 × 30 = 22,500 seconds = 375 minutes of ideal time, so performance is 375 ÷ 420 = 89.3%. 30 pieces were rejected, so quality is 720 ÷ 750 = 96%.
OEE = 0.875 × 0.893 × 0.96 = 75%. A quarter of the planned time produced nothing sellable — and the breakdown says most of it went on downtime and slow running, not on rejects.
What counts as planned time and downtime
Planned production time is the shift minus planned breaks and periods with no work scheduled. Downtime is everything that stopped the machine within that time — breakdowns, setups and changeovers, waiting for material or an operator. Counting setups as downtime is standard; leaving them out flatters availability.
Ideal cycle time is the fastest the machine can make one good part under ideal conditions — the design or best demonstrated rate, not the average. Using the average hides speed losses and pushes performance towards 100%.
Making OEE a daily number
OEE is most useful tracked per machine, per shift, with a reason recorded for every stoppage. Downtime reason codes show whether the biggest loss is breakdowns, setups or material shortages — and each needs a different fix. Production software that logs job start, stop and rejects can work out OEE without anyone filling a register.
Questions people ask.
What is the OEE formula?
OEE = Availability × Performance × Quality. Availability = run time ÷ planned time, Performance = ideal cycle time × total count ÷ run time, Quality = good count ÷ total count.
What is OEE?
Overall equipment effectiveness — the share of planned production time that produced good parts at the ideal speed. 100% means no stoppages, no slow cycles and no rejects.
What is a good OEE score?
About 85% is considered world class for discrete manufacturing. Many plants measuring for the first time find 40–60%, which means there is significant hidden capacity.
Can performance be more than 100%?
Only if the ideal cycle time entered is slower than what the machine can actually do. If you see over 100%, correct the ideal cycle time to the true best rate.
Are setup and changeover time counted in OEE?
Yes — setups and changeovers within planned production time are availability losses. Excluding them makes availability look better than it is.
How is OEE different from machine utilisation?
Utilisation only asks how long the machine ran. OEE also asks whether it ran at full speed and made good parts, so it is always equal to or lower than availability.
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