# What is my OEE?

Works out overall equipment effectiveness (OEE) from planned production time, downtime, ideal cycle time, total parts and good parts: availability × performance × quality.

- Page: https://www.acalculator.org/logistics/oee-calculator
- JSON spec: https://www.acalculator.org/logistics/oee-calculator.json
- Version: 79b73e34281e

## Default answer

Example with the default inputs (Planned production time 450 min, Downtime 45 min, Ideal cycle time 30 s, Total parts made 760, Good parts 741): With 90% availability, 93.83% performance and 97.5% quality, OEE is 82.33%.

## Inputs

| Key | Label | Description |
| --- | --- | --- |
| planned | Planned production time | The time the machine was scheduled to run: the shift less planned breaks and planned stops. |
| down | Downtime | Unplanned stops inside the planned time: breakdowns, changeovers, adjustments, waiting for material. |
| cycle | Ideal cycle time | The fastest time to make one part, at the machine’s design speed. |
| total | Total parts made | Every part made in the run time, good parts and rejects. |
| good | Good parts | Parts that were right the first time, with no scrap or rework. |

## Outputs

| Key | Label | Description |
| --- | --- | --- |
| oee | OEE | Availability × performance × quality: good parts × ideal cycle time ÷ planned production time. |
| availability | Availability | Run time ÷ planned production time. |
| performance | Performance | Ideal cycle time × total parts ÷ run time: the speed against the design speed. |
| quality | Quality | Good parts ÷ total parts. |
| runTime | Run time | Planned production time − downtime, in minutes. |
| productive | Fully productive time | Good parts × ideal cycle time, in minutes: the time the good parts would take at the ideal speed. |

## Method

Run time = planned production time − downtime. Availability = run time ÷ planned production time. Performance = ideal cycle time × total parts ÷ run time. Quality = good parts ÷ total parts. OEE = availability × performance × quality = good parts × ideal cycle time ÷ planned production time.

## Assumptions

- Planned production time already leaves out planned breaks and planned stops; downtime is only the unplanned stops inside it.
- Good parts are those right the first time; reworked parts count as rejects.
- Performance cannot pass 100%: an ideal cycle time that does that is set too long.

## Worked examples

1. planned = 60,000, down = 6,000, cycle = 51.3, total = 1,000, good = 990 gives availability = 90%, performance = 95%, quality = 99%, oee = 84.645%. Source: Lean Enterprise Institute, Lean Lexicon: Overall Equipment Effectiveness (availability rate × performance rate × quality rate; 90% × 95% × 99% = 84.6%), https://www.lean.org/lexicon-terms/overall-equipment-effectiveness/.
2. planned = 27,000, down = 2,700, cycle = 30, total = 760, good = 741 gives runTime = 24,300, availability = 90%, performance = 93.82716%, quality = 97.5%, oee = 82.333333%, productive = 22,230. Source: Lean Enterprise Institute, Lean Lexicon: Overall Equipment Effectiveness (availability rate × performance rate × quality rate; 90% × 95% × 99% = 84.6%), https://www.lean.org/lexicon-terms/overall-equipment-effectiveness/ (the three rates multiplied).
3. planned = 25,200, down = 0, cycle = 60, total = 400, good = 400 gives availability = 100%, quality = 100%, performance = 95.238095%, oee = 95.238095%. Source: Lean Enterprise Institute, Lean Lexicon: Overall Equipment Effectiveness (availability rate × performance rate × quality rate; 90% × 95% × 99% = 84.6%), https://www.lean.org/lexicon-terms/overall-equipment-effectiveness/.

## FAQ

### How do you calculate OEE?

OEE = availability × performance × quality. The Lean Lexicon’s example: 90% availability, 95% performance and 99% quality give 0.90 × 0.95 × 0.99 = 84.6% OEE.

### What is a shortcut for OEE?

Multiply out the three rates and most terms cancel: OEE = good parts × ideal cycle time ÷ planned production time. With 741 good parts, a 30-second ideal cycle and 450 planned minutes: 741 × 30 ÷ 27,000 = 82.33%.

### What does each part of OEE measure?

Availability counts time lost to stops (breakdowns, changeovers, adjustments). Performance counts speed lost to running slower than the design speed and to short stops. Quality counts parts lost to scrap and rework. Together they cover the six big losses of total productive maintenance.

### Should planned breaks count as downtime?

No. Take planned breaks, meals and planned stops off the shift first; what is left is the planned production time. Downtime is only the unplanned stops inside it.

### Why can performance not be over 100%?

Performance compares the parts made with what the machine could make at its ideal speed. If the parts at the ideal cycle time add up to more than the run time, the ideal cycle time is set too long, the count is too high, or downtime is overstated. The calculator gives no answer until the numbers fit.

### Do reworked parts count as good?

No. Quality counts only parts made right the first time. A part that needs rework counts as a quality loss, like scrap.

## Sources

- Lean Enterprise Institute, Lean Lexicon: Overall Equipment Effectiveness (a total productive maintenance measure: availability rate measures downtime losses as a percentage of scheduled time; performance rate measures operating speed losses; quality rate expresses scrap and rework as a percentage of total parts run; availability rate × performance rate × quality rate = OEE; example 0.90 × 0.95 × 0.99 = 84.6%). https://www.lean.org/lexicon-terms/overall-equipment-effectiveness/ (retrieved 2026-10-18)