In practice, almost every factory knows that one weekly figure that comes out of Excel by hand, is half right and lands on the table too late. The problem is not the formula, it is that a single summarised percentage does not show where the loss actually sits.
The OEE formula
OEE = Availability × Performance × Quality
- Availability = actual run time ÷ planned production time
- Performance = (ideal cycle time × total produced) ÷ actual run time
- Quality = approved products ÷ total produced
Worked example
A line runs a shift of 480 minutes, of which 30 minutes are a planned stop. The planned production time is therefore 450 minutes.
- Unplanned downtime 90 min → run time 360 min → Availability = 360 ÷ 450 = 80%
- Ideal cycle time 1.0 min/unit, 300 units → Performance = (1.0 × 300) ÷ 360 = 83.3%
- 285 approved out of 300 → Quality = 285 ÷ 300 = 95%
- OEE = 0.80 × 0.833 × 0.95 = 63.3%
85% counts internationally as “world class”; most factories sit between 40% and 60%.
What 37% loss means
That 63% says that well over a third of your planned production time does not end up in good products. On a line you can barely staff any more heavily, given the labour shortage of 2026, that loss is often cheaper to win back than an extra shift or a new line.
Why you steer on the three separate factors, not on the OEE figure
A weekly average of 63% does not tell you whether the problem sits in downtime, speed loss or rejects. Only once you track the three factors separately and record downtime by cause and by shift can you adjust in a targeted way during the shift, instead of performing an autopsy afterwards.
Those underlying figures come from your existing machines: VDS reads out downtime and counts via standard interfaces (such as OPC UA and Modbus), or via separate sensors where a machine gives no data, without replacing your machinery. The data stays in your own environment. The recording runs automatically in the background, so it does not become an extra job for the maintenance department. VDS supplies the measurement layer and the figures; what you improve with them stays your decision.
A small first step
If you want to know where your biggest OEE loss sits on one line, start with a single line rather than the whole factory. Let the baseline measurement on one line show what there is to gain.
Frequently asked questions
What does OEE mean?
Overall Equipment Effectiveness: the extent to which a line produces what is theoretically possible, as availability × performance × quality.
What is a good OEE score?
85% counts as world class; 40–60% is common in discrete manufacturing. The trend and the breakdown say more than the absolute value.
What is the difference between OEE and availability?
Availability is one of the three factors and looks only at downtime.
How do you raise your OEE?
Tackle the biggest source of loss for each factor. That starts with recording downtime by cause.
Where does the data for OEE come from?
From the machines themselves, via standard interfaces or separate sensors; the existing machinery does not have to be replaced and the measurement runs automatically in the background.
