Free tool · Production and quality
OEE Calculator
Work out Overall Equipment Effectiveness from availability, performance and quality, and see where the time went
- Free
- No signup
- Indian rules
Time
· in minutes, for one shift or any periodIdeal speed
Output
The six big losses
- Availability is lost to equipment failure and to setups and adjustments (changeovers).
- Performance is lost to idling and minor stops, and to running below the ideal speed.
- Quality is lost to process defects in steady running, and to reduced yield while the process settles after start-up.
- Count reworked parts as rejects. Quality in OEE means good the first time.
- Breaks and planned no-production time are left out of OEE. Changeovers and setups are not: they are stop time.
Results
OEE
78.6%
330.2 of 420 planned minutes made good parts at the ideal speed
Run time ÷ planned production time = 378 ÷ 420 min
World-class target 90%. Losses here: breakdowns, setups and changeovers.
Ideal cycle time × total count ÷ run time = 14 s × 1,458 ÷ 22,680 s
World-class target 95%. Losses here: minor stops and slow running.
Good count ÷ total count = 1,415 ÷ 1,458
World-class target 99%. Losses here: defects and start-up rejects.
Where the planned time went
- Fully productive: 330.2 min
- Quality loss: 10 min
- Speed loss: 37.8 min
- Stop time: 42 min
OEE: 90% × 90% × 97.05% = 78.61%
Check: good count × ideal cycle time ÷ planned time = 1,415 × 14 s ÷ 25,200 s = 78.61%
Benchmark: Nakajima's world-class figures of 90% × 95% × 99% multiply to 84.6%, usually quoted as 85%. Vorne reports most plants run nearer 60%. Track your own trend first.
OEE is only as good as the stop times and counts behind it. Use the true ideal cycle time, not a rate you usually reach, or performance will look better than it is. The world-class targets suit discrete manufacturing and are a guide, not a standard.
How it works
What this tool does.
Calculate OEE for a machine or line from shift time, breaks, stop time, ideal cycle time, total count and good count. See availability, performance and quality, the minutes lost to stops, slow running and rejects, and how each compares with the world-class figures.
Enter the shift length and planned breaks, which give the planned production time. Enter the stop time: breakdowns, changeovers, setups and any other stops while the line was meant to run. Give the ideal cycle time, the fastest the machine can make one part, in seconds per part or as parts per minute. Then enter how many parts were made in total and how many were good the first time. The calculator works out availability, performance and quality, multiplies them for OEE, and checks the answer with the simpler good count × ideal cycle time ÷ planned time. A bar shows how the planned minutes split into fully productive time, quality loss, speed loss and stop time, and each factor is set against Nakajima’s world-class targets.
Rules and dates last reviewed: October 2026
OEE Calculator formula
Planned production time = shift length − planned breaks. Run time = planned production time − stop time. Availability = run time ÷ planned production time. Performance = (ideal cycle time × total count) ÷ run time. Quality = good count ÷ total count. OEE = availability × performance × quality, which equals (good count × ideal cycle time) ÷ planned production time.
Worked example
A plastic moulding unit in Rajkot runs an 8-hour (480-minute) shift with two 15-minute tea breaks and a 30-minute lunch. The machine stops for a 25-minute mould change and a 17-minute heater fault. Its ideal cycle time is 14 seconds a part. The shift moulds 1,458 parts, of which 1,415 pass first time.
- Planned production time = 480 − 60 = 420 minutes
- Run time = 420 − (25 + 17) = 378 minutes
- Availability = 378 ÷ 420 = 90.0%
- Performance = 14 × 1,458 ÷ (378 × 60) = 20,412 ÷ 22,680 = 90.0%
- Quality = 1,415 ÷ 1,458 = 97.05%
- OEE = 90.0% × 90.0% × 97.05% = 78.6%
- Check: 1,415 × 14 ÷ (420 × 60) = 19,810 ÷ 25,200 = 78.6%
OEE is 78.6%: only about 330 of the 420 planned minutes (19,810 seconds) made good parts at full speed. Availability already meets the world-class 90%, but performance is 5 points short of 95% and quality about 2 points short of 99%, so cutting minor stops and slow cycles is the biggest gain.
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Questions
OEE Calculator, answered.
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What is the OEE formula?
OEE = availability × performance × quality. Availability is run time ÷ planned production time, performance is (ideal cycle time × total count) ÷ run time, and quality is good count ÷ total count. Multiplied out, OEE is the same as good count × ideal cycle time ÷ planned production time.
What is a good OEE score?
An OEE of 85% is often called world-class. It comes from Seiichi Nakajima’s book Introduction to TPM, which set targets of 90% availability, 95% performance and 99% quality; those multiply to 84.6%. Vorne, which runs OEE.com, says most manufacturers are closer to 60% and that the targets suit discrete manufacturing. Improving your own OEE matters more than the absolute number.
What are the six big losses in OEE?
Equipment failure and setup and adjustments reduce availability. Idling and minor stops and reduced speed reduce performance. Process defects and reduced yield at start-up reduce quality. Grouping stops and rejects this way shows which kind of loss costs you most.
Should breaks and changeovers be counted as downtime?
Breaks and time when the line is not meant to run are taken out before OEE is worked out, so they do not count against it. Changeovers and setups during production time are stops: they count as stop time and lower availability.
What is ideal cycle time?
It is the fastest the process can make one part under the best conditions, often the machine’s rated speed. Do not use your usual or average cycle time: performance would then hide slow running and could even come out above 100%.
Do reworked parts count as good parts in OEE?
No. Quality in OEE counts only parts that are right the first time. A part that is reworked and then passes is still counted as a reject, because the machine time spent making it the first time was lost.
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