Key takeaways
- OEE = Availability × Performance × Quality - the single number for how productive your planned time really is.
- 85% is world-class for discrete manufacturing; 60% is typical; below 40% means fast, large upside.
- OEE losses sort into six big losses across availability, performance and quality.
- Most reported OEE is overstated because short micro-stops never get logged.
Overall Equipment Effectiveness (OEE) is the gold-standard metric for manufacturing productivity. In one number, it tells you how much of your planned production time is genuinely productive - making good parts at full speed with no stops. An OEE of 100% is perfect production: only good parts, as fast as the machine can run, with zero downtime.
It's powerful because it's honest. A line can look busy and still have an OEE of 55% - and that gap is money. Here's exactly how it works.
The OEE formula
OEE is the product of three factors:
OEE = Availability × Performance × Quality
- Availability = Run Time ÷ Planned Production Time.
Run Time = Planned Production Time − all stop time (breakdowns, changeovers, every stop). - Performance = (Ideal Cycle Time × Total Count) ÷ Run Time.
Captures speed loss and short stops - running slower than nameplate. - Quality = Good Count ÷ Total Count.
The share of parts that pass first time (rework counts as a defect).
A worked example
Take an 8-hour shift (480 minutes) with 60 minutes of total stops, an ideal cycle time of 1 second per piece, 22,000 pieces produced and 500 rejects:
| Factor | Calculation | Result |
|---|---|---|
| Availability | 420 ÷ 480 | 87.5% |
| Performance | (1 × 22,000) ÷ 25,200s | 87.3% |
| Quality | 21,500 ÷ 22,000 | 97.7% |
| OEE | .875 × .873 × .977 | 74.7% |
Skip the spreadsheet - our free calculator does this live and overlays the world-class benchmark.
What is a good OEE score?
The widely accepted benchmarks for discrete manufacturing:
| OEE | Rating | What it means |
|---|---|---|
| 100% | Perfect | Only good parts, full speed, no stops (theoretical). |
| 85% | World-class | ≈ 90% availability, 95% performance, 99.9% quality. |
| 60% | Typical | Common - and a clear signal of room to improve. |
| 40% | Low | Not unusual for plants just starting to measure. Large, fast upside. |
One caution: benchmarks vary by industry and process. A continuous process line and a high-changeover job shop are not comparable. Compare yourself to your own trend first, then your industry.
The six big losses
OEE is most useful when you trace each lost point to a cause. The "six big losses" map onto the three factors:
| Factor | Loss | Examples |
|---|---|---|
| Availability | Breakdowns | Equipment failure, unplanned stops |
| Setup & adjustments | Changeovers, warm-up, tooling | |
| Performance | Idling & minor stops | Jams, misfeeds, sensor blocks - micro-stops |
| Reduced speed | Running below nameplate rate | |
| Quality | Process defects | Scrap and rework in steady state |
| Reduced yield | Defects during startup/changeover |
How to improve OEE
- Measure automatically. Manual logs miss the small losses - start from machine data, not clipboards.
- Attack the biggest factor first. If performance is lowest, you have a micro-stop or speed problem, not a breakdown problem.
- Find the true cause. "Performance loss" isn't actionable; "the labeller jams on wet cartons" is.
- Close the loop. Detect → diagnose → fix → verify the same failure stops recurring.
Why your reported OEE is probably too high
Here's the trap. OEE only subtracts the downtime you record - and short stops under about five minutes almost never get logged. So their lost time vanishes from availability and shows up (if at all) as a vague performance gap. The result: reported OEE commonly runs 10–18 points above reality.
That invisible loss is the hidden factory. If your OEE looks acceptable but output doesn't match, that's almost always where it's going. You can size yours here.
Fabrico reads OEE directly from the machine and shows the true cause of every stop, automatically. No manual logging.
Frequently asked questions
What is OEE in simple terms?
The percentage of your planned production time that's truly productive - good parts, at full speed, with no stops.
Is OEE the same as utilization or TEEP?
No. OEE measures planned production time only. TEEP (Total Effective Equipment Performance) extends OEE to all calendar time, so it also reflects whether you're scheduling the asset enough.
Can OEE be over 100%?
No. If your math produces over 100%, an input is wrong - usually the ideal cycle time is set too slow.
How often should I measure OEE?
Continuously, per machine. Shift- or day-level averages hide the patterns; the value is in seeing when and where losses happen.