Every availability and OEE number is a fraction, and planned production time is the bottom of it. Get the base wrong and every number built on it is wrong too.
The formula
Planned production time = Shift time − Planned stops. Planned stops are the ones decided in advance: meal and tea breaks, scheduled maintenance, meetings, and periods with no orders.
Unplanned stops — breakdowns, waiting for material, setup overruns — stay inside planned production time. They are the losses OEE exists to show.
A worked example
One machine, one shift (illustrative numbers):
Shift length
- Minutes
- 480
Lunch break
- Minutes
- − 30
Two tea breaks
- Minutes
- − 20
Planned production time
- Minutes
- 430
Actual running time
- Minutes
- 344
| Item | Minutes |
|---|---|
| Shift length | 480 |
| Lunch break | − 30 |
| Two tea breaks | − 20 |
| Planned production time | 430 |
| Actual running time | 344 |
Availability = 344 ÷ 430 = 80%. Measured against the full 480-minute shift it would read 72% — a machine blamed for breaks it was never meant to run through. Try it in the availability calculator.
Getting the base right
The common mistake runs the other way: calling more and more stops “planned” until availability looks healthy. If it wasn’t decided before the shift started, it isn’t a planned stop.
ThingConnect takes planned stops from the shift setup, so a scheduled break isn’t counted as lost time, and a shift’s parts target holds flat through lunch instead of running ahead of the machine. Everything else stays in the base, where it belongs. More in the OEE guide.