OEE Calculator
Overall Equipment Effectiveness measures how much of your planned production time produces good units at full speed. It multiplies availability, performance and quality, which is why three factors at 90% each give 72.9% rather than 90%. This calculator shows the three factors as equals and names the one costing you most, because a single percentage tells an operations manager nothing they can act on.
For the shift or period being measured.
Breakdowns, changeovers, material waits. Not planned breaks — that is the second most common input error.
The fastest the machine can produce one unit. Nameplate speed, not average.
Good and bad.
OEE
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Enter your details to see the estimate.
| Loss analysis | Value |
|---|---|
| Planned production time | — |
| Run time | — |
| Good units | — |
| Biggest loss | — |
| Lost output to that factor | — |
| If this factor reached 90% | — |
Calculated in your browser. Your figures never reach our servers, and nothing you type here creates a record.
An estimate based on the figures you entered. Model your own numbers before committing to a decision.
The concept
Three factors, one number
OEE measures how much of your planned production time produces good units at full speed. It multiplies three factors.
Availability — did the machine run when it was supposed to? Losses are breakdowns, changeovers, material waits, operator absence.
Performance — did it run at full speed? Losses are minor stops, reduced speed, idling.
Quality — was the output good first time? Losses are rejects, rework, startup scrap.
They multiply rather than average, which is why OEE falls quickly. Three factors at 90% each give 72.9%, not 90%.
That multiplication is the point. It exposes that a plant “running well” on three separate measures is losing more than a quarter of its capacity.
Show the working
The OEE formula
run time = planned − unplanned downtimeavailability = run time ÷ planned timeperformance = (ideal cycle × units) ÷ run timeCycle in seconds, run time converted to seconds.quality = good units ÷ total unitsOEE = availability × performance × qualityWorked example. A shift with 480 minutes planned and 47 minutes of unplanned downtime. Ideal cycle time 1.5 seconds per unit. 14,200 units produced, 320 rejected.
Run time is 433 minutes. Availability = 433 ÷ 480 = 90.2%. Performance = (1.5 × 14,200) ÷ (433 × 60) = 21,300 ÷ 25,980 = 82.0%. Quality = 13,880 ÷ 14,200 = 97.7%. OEE = 72.3%.
The biggest loss here is performance — minor stops and reduced speed, not breakdowns. That is a different investigation from the one a maintenance manager would have started from the downtime figure alone.
The question everyone gets wrong
OEE is a comparison against yourself, not against other factories
First: comparing OEE across different plants or products. OEE depends heavily on how planned production time is defined and what ideal cycle time is set to. Two factories can report 65% and 80%, and the second may be the less efficient one — it has simply set a softer cycle time. OEE is only meaningful as a trend on the same line with the same definitions.
Second: chasing the OEE number rather than the loss. OEE is a diagnostic, not a target. A plant that improves OEE by relaxing its ideal cycle time has improved nothing. The value is in the factor breakdown — which of the three is costing you most, and what specifically is causing it.
The related discipline is TEEP, which measures against all calendar time rather than planned time. TEEP answers “how much of the asset are we using?” while OEE answers “how well is the plant running when it runs?” Two different questions with two different owners.
Benchmarks
What the number means
| OEE | Reading |
|---|---|
| 100% | Theoretical only — every unit good, at full speed, no stops |
| 85% | Widely cited as world class for discrete manufacturing |
| 60% | Typical for a discrete manufacturer |
| 40% | Common for plants without formal OEE measurement |
The 85% world-class figure comes from a common decomposition of 90% availability × 95% performance × 99% quality. It is widely used rather than a formal standard.
A note worth making for UAE plants. Heat, dust and humidity affect availability more than in temperate markets. Calendar-based maintenance intervals imported from a European manual are consistently wrong here, and unplanned downtime often traces back to a service schedule that assumed different conditions.
Frequently asked questions
OEE questions
What is OEE?
Overall Equipment Effectiveness: the proportion of planned production time that produces good units at full speed. It is the product of availability, performance and quality.
How do I calculate OEE?
Availability is run time divided by planned time. Performance is ideal cycle time times units produced, divided by run time. Quality is good units divided by total units. Multiply the three.
What is a good OEE score?
85% is widely cited as world class for discrete manufacturing, 60% is typical, and around 40% is common for plants without formal measurement. Treat these as direction rather than targets, since OEE depends heavily on how you define planned time.
What is the difference between OEE and TEEP?
OEE measures against planned production time and answers how well the plant runs when it runs. TEEP measures against all calendar time and answers how much of the asset you are using. Two different questions with two different owners.
Why is my performance factor above 100%?
The ideal cycle time is wrong — it has been entered as an average rather than nameplate speed. Performance above 100% is always an input problem, never a genuine result.
Should planned breaks count as downtime?
No. Planned breaks are excluded from planned production time rather than counted as downtime. Including them understates availability and makes the figure incomparable with anyone else’s.
What are the six big losses?
Breakdowns and setup or changeover losses hit availability; minor stops and reduced speed hit performance; startup rejects and production rejects hit quality. Every OEE point lost traces back to one of the six.