The Page Followers metric comes directly from the official API of Facebook. It shows the total number of followers of your Page at the moment you generate the report. Facebook calculates this number by subtracting those who unfollowed the Page.
Unlike metrics like impressions or clicks that add up values day by day and consolidate the result, this metric functions differently. The Facebook API continues to update this data even for past periods, which is why it does not have a fixed historical value.
Why the value might change in different reports analyzing the same period.
Each report shows the data returned by the API at the moment of generation, acting like a snapshot of that moment.
In the case of Page Followers, Facebook constantly recalculates this total even for past periods. The platform periodically removes deleted, banned, fake, or inactive accounts. This removal retroactively affects the numbers, including periods you have already checked.
Therefore, if you generate a report today for the last month and generate another for the same month in a few weeks, the number of Page Followers might appear different between the two.
Is this a report error?
No, this is not an error. Reportei displays exactly the value the Facebook API returns at the moment of the query, whether in report or dashboard generation or when you add the metric. We do not perform any additional calculation or adjustment on this data.
This variation reflects how Facebook itself maintains the metric in its database. It is not possible to lock or consolidate this number for a specific period because Meta can recalculate it at any time. As each report is a snapshot of the query moment, comparing reports generated on different dates can highlight this difference.
This variation only affects the Page Followers metric. Other report data such as engagement, reach, and impressions remain normal.