When you work with demand forecasting in Business Central, two of the forecast views recalculate automatically when you open them, while the third does not. Knowing which is which prevents you from acting on outdated numbers.
The forecast per period view and the forecast per dimension view update automatically every time you enter them. The view where you enter many items in one period does not update automatically. You have to update it manually.
The manual update on that third view exists for performance reasons. If it recalculated every time you opened it, a forecast with 5,000 or 10,000 items would take too long to load.
Forecast per period updates automatically
When you open the forecast per period, it calculates and updates the data right away. For example, in the month of May you might see 60 on inventory. If you add another 40, leave the view, and enter it again, the view recalculates automatically and shows 100.
Forecast per dimension updates automatically
The forecast per dimension behaves the same way. It calculates when you open it. If you added 40 to item number 1000, that view already includes the change when you open it. Updating the forecast afterwards will not change anything, because the numbers are already current.
Forecast per item in one period must be updated manually
The view where you enter many items in one period is the exception. It does not update automatically. For example, the first line on item 1000 might show 520. When you update the forecast, it changes to 516, reflecting the actual current data.
The reason is performance. If this view recalculated every time you removed a filter, left the page, and re-entered it, a forecast with 5,000 or 10,000 items would never finish loading. The calculation would run again and again on a large dataset, making the page unusable. To avoid this heavy load, you update this view manually.
What to do in practice
Remember that the forecast per period and the forecast per dimension always show current data when you open them. The view with many items in one period shows the last calculated values until you trigger an update yourself. Before you rely on the numbers in that view, run the update so you are working with the correct figures.
Q&A
Which forecast views in Business Central update automatically?
The forecast per period and the forecast per dimension both recalculate automatically every time you open them.
Why does the forecast with many items in one period not update automatically?
For performance reasons. Recalculating every time you enter the page would make a forecast with 5,000 or 10,000 items extremely slow to load, so you update this view manually instead.
How do I get current numbers in the forecast per item in one period view?
Run the update manually. The view keeps showing the last calculated values until you trigger an update, after which it reflects the actual current data.