What OEE measures.
OEE (Overall Equipment Effectiveness) is the ratio between fully productive time, the time that produced good parts at the ideal rate, and planned production time: an OEE of 80% means that 8 minutes out of 10 of planned production made good parts.
In France the same metric is called TRS and is standardised by NF E60-182. Both describe time as a cascade. Each level removes one family of losses:
| Time | What you remove to reach the next level |
|---|---|
| Planned production time | Breakdowns, setups, changeovers |
| Run time | Small stops and reduced speed |
| Net run time | Scrapped or reworked parts |
| Fully productive time | What is left: the time that made good parts |
Planned stops such as breaks and scheduled maintenance are already out of planned production time. OEE judges the equipment and the team, not the schedule.
The OEE formula.
OEE is the product of three factors. Each one isolates a family of losses:
- Availability = run time ÷ planned production time. It drops with breakdowns and setups.
- Performance = (total parts × ideal cycle time) ÷ run time. It drops with small stops and reduced speed.
- Quality = good parts ÷ total parts. It drops with scrap and rework.
OEE = availability × performance × quality.
The three factors simplify into the short form, the fastest to compute:
OEE = (good parts × ideal cycle time) ÷ planned production time.
The ideal cycle time is the nameplate rate of the machine, or the one validated by your engineering team. Using a "realistic" cycle time instead inflates performance and hides part of the losses.
A worked example.
One shift on a packaging line (example figures):
| Input | Value |
|---|---|
| Planned production time | 450 min (8 hour shift minus a 30 min break) |
| Breakdowns and setups | 45 min |
| Ideal cycle time | 30 s per part |
| Total parts | 750 |
| Good parts | 720 |
Step by step:
- Run time: 450 − 45 = 405 min. Availability = 405 ÷ 450 = 90%.
- Net run time: 750 parts × 30 s = 375 min. Performance = 375 ÷ 405 = 92.6%.
- Fully productive time: 720 parts × 30 s = 360 min. Quality = 720 ÷ 750 = 96%.
- OEE = 90% × 92.6% × 96% = 80%. Same result with the short form: 360 ÷ 450.
On this shift the biggest loss is availability: 45 minutes, against 30 for performance and 15 for quality. That is where the first lever is.
Calculate your OEE.
Enter the figures of one shift or one day. The result updates as you type and shows the factor that costs you the most minutes.
The figures you enter stay in your browser: nothing is sent.
Free Excel template
A production dashboard ready to fill in: one row per day and per machine, OEE and its three factors, MTBF, MTTR and takt time computed with formulas. Get it by email.
OEE, TRS and TEEP.
The metrics share the same numerator, fully productive time. Only the denominator changes:
| Metric | Formula | What it judges |
|---|---|---|
| OEE (TRS in France) | Fully productive time ÷ planned production time | Equipment and team, during the time planned for production |
| TRG (French standard) | Fully productive time ÷ opening time | Also the weight of planned stops |
| TEEP (TRE in France) | Fully productive time ÷ calendar time | Use of the equipment over the whole calendar, 24/7 |
OEE is the one to run the shop floor with. TRG and TEEP serve organisation and investment decisions: adding a shift, or buying a second machine.
What OEE to aim for.
The most quoted benchmark is 85%. It is the world class level given by Seiichi Nakajima, who introduced TPM, in his 1984 book (oee.com). The same site notes that most manufacturers are closer to 60%.
Two rules make that benchmark useful:
- Compare a line with itself. OEE depends on the product, the batch sizes and the way stops are counted. Its progress, week after week, tells you more than a comparison with another plant.
- Look at the three factors, not just OEE. Two lines at 70% can have opposite levers: one loses time to breakdowns, the other to scrap.
Raising OEE.
Each factor has its own levers:
- Availability. Fewer breakdowns and shorter repairs: MTBF and MTTR measure them (MTBF and MTTR calculator). Faster changeovers count too.
- Performance. Small stops and reduced speed are hard to see because each one is short. An hourly record brings them out. Takt time then tells you whether the line keeps up with demand.
- Quality. A scrapped part used up its whole cycle time. Fixing the cause at the station that creates it pays twice: in quality and in machine time.
The first lever is the measurement itself. An OEE computed once a month arrives too late to act on a drift. An OEE updated every day shows the loss while it can still be fixed. A production dashboard puts these KPIs on one screen.
That is the mechanism we built for Maeva & Co, a property management company: exports are collected, figures computed and the dashboard consolidated every 24 hours, with no manual re-entry. More than 400 hours freed up per year.
Sources: title and scope of the French standard from its AFNOR listing (NF E60-182, May 2002); 85% benchmark and the 60% observation from oee.com.
OEE: what people ask us.
How do you calculate OEE?
Multiply three factors: availability (run time ÷ planned production time), performance (total parts × ideal cycle time ÷ run time) and quality (good parts ÷ total parts). The result equals good parts × ideal cycle time ÷ planned production time. Example: 90% × 92.6% × 96% = 80%.
What is a good OEE score?
The most quoted benchmark is 85%, the world class level from Seiichi Nakajima, who introduced TPM (1984). According to oee.com, most manufacturers are closer to 60%. The most useful comparison is your own line, week after week.
What is the difference between OEE and TRS?
None in substance. TRS, taux de rendement synthétique, is the French name of the same metric, standardised in France by NF E60-182. The same standard also defines TRG (good parts time over opening time) and TRE (over calendar time).
What is the difference between OEE and TEEP?
The denominator. OEE compares fully productive time with planned production time. TEEP compares it with all calendar time, 24 hours a day, 7 days a week, so it also shows the capacity left in unplanned hours.
Can I track OEE in Excel?
Yes, with one input row per day and per machine and the three factors as formulas. Our free Excel template does exactly that and you can get it by email from this page. Past a few production lines, manual input becomes the weak spot: that is where automatic consolidation from your exports takes over.