OEE Formula Quick Reference Table
OEE is simple arithmetic wrapped in definitions that people argue about. This table lists each formula in the OEE family with the inputs you need, so a team can agree on one version and use it everywhere.
| Metric | Formula | Unit | Inputs you must collect | Note |
|---|---|---|---|---|
Availability | Run time / Planned production time | % | Run time, planned production time | Planned production time excludes scheduled breaks and planned shutdowns in the classic OEE model. |
Run time | Planned production time - Stop time | minutes | Stop events with start and end | Count every stop above your minimum threshold, including changeovers. |
Performance | (Ideal cycle time x Total count) / Run time | % | Ideal cycle time, total count, run time | Ideal cycle time must come from the best demonstrated or rated speed, not the average. |
Performance (rate form) | Actual rate / Ideal rate | % | Actual units per hour, ideal units per hour | Equivalent to the cycle time form when run time is measured correctly. |
Quality | Good count / Total count | % | Good count, total count | Rework counts as not good in first pass OEE. |
OEE | Availability x Performance x Quality | % | The three factors above | Multiply as fractions, then show as a percent. |
OEE (time form) | (Good count x Ideal cycle time) / Planned production time | % | Good count, ideal cycle time, planned time | Same answer as the three factor form; useful as a cross check. |
Fully productive time | Good count x Ideal cycle time | minutes | Good count, ideal cycle time | The time that produced only good parts at ideal speed. |
Loading | Planned production time / Calendar time | % | Planned production time, calendar time | Shows how much of the calendar the plant chooses to run. |
TEEP | OEE x Loading | % | OEE, loading | TEEP is OEE measured against all calendar time. |
Utilization | Actual run time / Scheduled time | % | Run time, scheduled time | Not the same as availability if your scheduled time includes planned stops. |
MTBF | Total operating time / Number of failures | hours | Operating hours, failure count | Use operating time, not calendar time. |
MTTR | Total repair time / Number of repairs | hours | Repair durations, repair count | Decide in advance whether waiting for parts is included. |
Inherent availability | MTBF / (MTBF + MTTR) | % | MTBF, MTTR | A design view that ignores planned maintenance and logistics delay. |
Takt time | Available production time / Customer demand | minutes per unit | Available time, demand | A demand based pace, not a machine speed. |
First pass yield | Units passed first time / Units started | % | Units started, units passed without rework | Differs from the quality factor if you start units that are never counted as total count. |
Scrap rate | Scrapped units / Total units produced | % | Scrap count, total count | Often reported alongside OEE quality loss. |
Changeover share | Total changeover time / Planned production time | % | Changeover durations | A direct view of the setup loss inside availability. |
Cycle time ratio | Ideal cycle time / Actual average cycle time | % | Ideal and actual cycle time | Quick performance estimate when you lack counts. |
OEE loss (points) | 100% - OEE | % | OEE | Split the loss across availability, performance and quality to prioritise action. |
Definitions vary by plant. Write down which time bases and thresholds you use so numbers stay comparable between lines and over time.
Get OEE calculated from your ERP and MES data
Optional review of how your stop, count and cycle time data could feed these formulas automatically.
Optional. The tool and every export work without this. No spam.
How to use the table
Search by metric name or by an input such as ideal cycle time. Find the formula, check the inputs column to see what you must record at the machine, then read the note for the usual trap. Use the PDF export as a shared definition sheet for a line, a plant or an ERP project, so everyone calculates the same way.
- Pick one time base and stick to it
- Document the minimum stop length you count
- Confirm which count your ERP backflushes
The method behind OEE
OEE splits lost production into three groups: stops (availability), slow running and small stops (performance) and defects (quality). Multiplying the three factors gives the share of planned time that produced good parts at ideal speed. TEEP widens the base to all calendar time so that unused shifts also show up as a loss. MTBF and MTTR explain the availability factor from the maintenance side.
Reading the numbers
A line at 85% availability, 90% performance and 98% quality has an OEE of about 75%. The weakest factor is not always the best place to start; pick the loss that is cheapest to fix and largest in minutes. Compare lines only when they share the same definitions of ideal cycle time and planned time.
Common mistakes
Teams most often use the average cycle time as the ideal, which hides performance loss. Others leave changeovers out of downtime, count rework as good, or compare OEE across lines that use different planned time rules. Fix the definitions before you chase the number.
Frequently Asked Questions
Is OEE the same as productivity?
No. OEE measures how well a machine or line uses its planned time to make good parts at ideal speed. Productivity usually compares output to labour or cost input. A line can have a high OEE and poor labour productivity, or the reverse.
What ideal cycle time should I use?
Use the fastest rate the equipment can sustain with good quality, from the rated speed or the best demonstrated run. Do not use the average. If you use the average, performance will look close to 100% and the speed losses will be invisible.
Should planned maintenance count against OEE?
In the classic model, planned downtime outside planned production time is excluded, and TEEP shows it as a loss. Many plants count it inside OEE instead. Either is fine if documented and used consistently across all lines.
Can OEE be above 100%?
Not if the inputs are right. A figure above 100% usually means the ideal cycle time is too slow, the count includes parts from another period, or the run time is understated. Treat it as a data error to investigate.
If the inputs live in your ERP and MES, we can help calculate these metrics from your production history without spreadsheet copying.
Related Tools
ISO 22400 Manufacturing KPI Reference
A plain language lookup of the manufacturing operations KPIs associated with ISO 22400, with the theme and the question each answers.
MES & Shop FloorDowntime Reason Code Hierarchy Reference
A starter list of downtime reason codes arranged in a hierarchy, mapped to the six big losses and to planned or unplanned status.
Developer ToolsOEE SQL Query Generator
Fill in your table and column names and get a SQL query that calculates availability, performance, quality and OEE per line per day.
Developer ToolsOEE Power BI DAX Measures Generator
Enter your table and column names and get DAX measures for availability, performance, quality and OEE that you can paste into a Power BI model.
More MES & Shop Floor tools
See all- Line Balancing Worksheet
- SMED Changeover Reduction Worksheet
- Finite Capacity Scheduling Worksheet
- Production Schedule Template
- Bottleneck Analysis Calculator
- Drum Buffer Rope Buffer Sizing Calculator
- Production Schedule Adherence Calculator
- Production Schedule Release Checklist
- Daily Production Schedule Board Worksheet