This free OEE calculator turns five shop-floor numbers into a single overall equipment effectiveness score, broken down into availability, performance and quality. Enter your planned production time, downtime, ideal cycle time, total units produced and reject units, and read your OEE percentage instantly — with each factor shown separately and compared to the 85% world-class benchmark. No sign-up, results update as you type.
How to calculate OEE
OEE multiplies three independent ratios, each of which can never exceed 100%:
OEE = Availability × Performance × Quality
- Availability =
run time ÷ planned production time, whererun time = planned time − downtime. It captures every minute lost to breakdowns, stoppages and changeovers. - Performance =
(ideal cycle time × total units) ÷ run time. It compares how fast the line actually ran to its ideal speed, so minor stops and slow running pull it down. - Quality =
good units ÷ total units, wheregood units = total units − rejects. It captures scrap, rejects and rework.
Worked example. A shift is scheduled for 480 minutes with 60 minutes of downtime, an ideal cycle time of 30 seconds per unit, 700 units produced and 25 rejects:
- Run time = 480 − 60 = 420 minutes
- Availability = 420 / 480 = 87.5%
- Performance = (30/60 × 700) / 420 = 350 / 420 = 83.3%
- Quality = (700 − 25) / 700 = 675 / 700 = 96.4%
- OEE = 87.5% × 83.3% × 96.4% ≈ 70.3%
That 70.3% is well above the typical 60% mark but still short of world-class — the biggest opportunity here is the 16.7% lost to slow running (performance).
What is a good OEE score?
OEE bands are a widely used yardstick for discrete manufacturing. Use them to gauge where a line sits and how much headroom remains:
| OEE score | Band | What it means |
|---|---|---|
| 85% and above | World-class | The benchmark for discrete manufacturing — ~90% availability, ~95% performance, ~99.9% quality. Hard to beat sustainably. |
| ~60% | Typical | Fairly common and a reasonable starting point, but it signals substantial room to improve on all three factors. |
| Below 40% | Low | Common for plants that have only just begun measuring. Large, very recoverable losses — usually quick wins available. |
Most factories that start measuring at 40–60% can climb toward world-class by systematically attacking downtime, slow cycles and scrap — the three things OEE makes visible.
The six big losses
OEE is the standard way to quantify the “six big losses” that TPM (Total Productive Maintenance) targets. Each loss maps to one of the three OEE factors:
- Availability losses — (1) unplanned stops / breakdowns and equipment failure, and (2) setup and changeover / adjustments.
- Performance losses — (3) idling and minor stops (small jams, sensor blocks, misfeeds), and (4) reduced speed / slow cycles running below ideal rate.
- Quality losses — (5) startup rejects and warm-up scrap, and (6) production rejects, rework and defects during steady-state running.
Because OEE rolls all six into one number, it lets you compare lines, shifts and machines on a level footing — and it tells you which loss is costing you the most.
From manual OEE to live OEE
A calculator answers one shift. Running a plant means tracking OEE on every line, every shift, every day — and the spreadsheet version drifts the moment someone forgets to log a stoppage. Inside OEMup ERP, OEE is tracked live from the shop floor: machine run/stop signals and production counts feed availability, performance and quality automatically, downtime reasons are captured at the source, and the six big losses are charted by line and shift — no end-of-day data entry. Start free or explore the full production & shop-floor features to see OEE handled end to end.
Frequently asked questions
How is OEE calculated?
OEE = Availability × Performance × Quality. Availability = run time / planned time (run time = planned − downtime); Performance = (ideal cycle time × total units) / run time; Quality = good units / total units. With 480 min planned, 60 min downtime, a 30-second cycle, 700 units and 25 rejects you get availability 87.5%, performance 83.3%, quality 96.4% and OEE ≈ 70.3%.
What is a good OEE percentage?
85% is world-class for discrete manufacturing (about 90% availability, 95% performance, 99.9% quality). Around 60% is typical and a fair starting point, while below 40% is common before a plant starts measuring and points to large, recoverable losses.
What is the difference between availability, performance and quality?
Availability measures lost time (run time / planned time), performance measures speed against the ideal cycle, and quality measures yield (good units / total units). Multiplying all three gives OEE, capturing every kind of loss in one number.
Can OEE be over 100%?
No. OEE multiplies three ratios that each cap at 100%. If performance or OEE shows above 100%, the ideal cycle time is set too slow or the run time is understated — re-check the ideal cycle against the machine’s fastest demonstrated speed.
Need another shop-floor tool? Try our free calculator library or the Production Cost Calculator.
Stop logging OEE in spreadsheets
OEMup tracks OEE live from the shop floor — availability, performance and quality, by line and shift, with no end-of-day data entry. Built for Indian manufacturing SMEs.
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