"Is this month better than last month?" cannot be answered by a single number; it is answered by two periods sitting side by side. That is why both the Insights and the Reports screen write the previous period next to every figure. This guide explains how periods are built, where the comparison window comes from, and what the percentage in a badge actually measures.
💡 The two screens do not offer identical period lists: Insights has Today and Last 28 days, Reports has Last 30 days. They speak the same calendar but use different windows, so do not expect the exact same number when you put them side by side.
The preset periods
On both screens a strip of pills sits to the right of the heading. Clicking a pill changes the period at once; there is no confirm button.
Insights
- Today — Today only.
- Last 7 days — Seven days back, today included.
- Last 28 days — The default. 28 days back, today included.
- Last 90 days — 90 days back, today included.
- This month — From the first of the month to today.
- Last month — The whole previous month (first to last day).
There is no 30-day option here, there is a 28-day one: Meta serves its daily metrics with a 28-day window of its own, and the panel uses the same length so that both sides agree.
Reports
- Last 7 days
- Last 30 days — The default.
- Last 90 days
- This month
- Last month
Reports has no custom range.
The custom range (Insights only)
When the presets are not enough you can enter your own window.
- Open Insights › Overview.
- Pick the first day in the Start field.
- Pick the last day in the End field.
- Click Apply. The period line in the header now shows the new range.
Its rules are:
- Both fields are capped at today. A future day cannot be selected; if one is submitted it is pulled back to today.
- If you enter the dates the wrong way round, the panel swaps them for you.
- The longest range is 365 days. Enter a longer one and the end day is kept while the start is trimmed.
- A broken or incomplete date falls back to the default period (Last 28 days) rather than showing an error.
- You can pick a day from this month even while "Last month" is selected: the fields are capped at today, not at the end of the selected period.
Where the comparison period comes from
The second line under the heading reads "Compared with: … – …". That window is always built the same way: the equally long period immediately before the one you chose.
Examples:
- With Last 7 days selected, the comparison is the seven days before those.
- With Last month selected, the comparison is the month before that — however many days it had.
- With a 10-day custom range such as 1–10 September, the comparison is 22–31 August.
The two windows neither overlap nor leave a gap between them. Day boundaries sit at midnight in the account's time zone and do not drift across a daylight-saving change.
How the change badge is calculated
A badge and a "Previously: {number}" line sit under every figure. The percentage in the badge is this formula:
(this period − previous period) ÷ previous period
The result is rounded to one decimal place. The badge can appear in four forms:
| Badge | When it appears |
|---|
| up 12.4% (green, upward arrow) | This period is higher than the previous one |
| down 8.1% (red, downward arrow) | This period is lower |
| No change / Unchanged | The two periods are identical |
| Previous period unknown / New | No ratio can be calculated |
Green does not always mean "up"
In Reports two metrics are read the other way round, because falling is good:
- Runs failed — a rise is red, a fall is green.
- First response time — getting shorter is green, getting longer is red.
For every other metric a rise is green and a fall is red.
"New" versus "Previous period unknown"
These are two different things and they appear on different screens:
- Reports › New: Nothing was recorded in the previous period and something was recorded in this one. No ratio is possible, but "it started from zero" is a true statement.
- Insights › Previous period unknown: The comparison window is entirely missing from the archive. The panel stores only what happened after you connected the account; if the comparison window reaches back before the archive began, the two totals cover different numbers of days and cannot be compared.
In the second case treating the missing days as zero would be wrong: comparing three days of data with seven days of data and printing a rise is worse than printing nothing.
A concrete example
A jeweller connects their account on 1 September. The first sync backfills 30 days, so the archive begins on 2 August.
- On 20 September they select Last 7 days: the period is 14–20 September, the comparison 7–13 September. Both are in the archive, so every badge shows a percentage.
- The same day they select Last 90 days: the period is 23 June – 20 September, the comparison 25 March – 22 June. The comparison window is older than the archive, so every badge reads "Previous period unknown".
- By December the same Last 90 days selection will show percentages, because the archive will have accumulated that much history.
This behaviour is not a fault, it is honesty: the panel never invents a number it does not have.
What the period does not affect
Three things are completely unaffected by the period, and not knowing this is the most common source of confusion.
- Audience demographics. They are a lifetime distribution, as the section's own description says.
- The post list and post metrics. Meta keeps post numbers as lifetime totals. That is why the Posts tab is not filtered by period: changing the pill does not change the list.
- The follower count itself. The last known value of the period is shown; it is never summed.
Common mistakes and how to fix them
- Treating "Last 28 days" and "Last 30 days" as the same. Insights uses 28, Reports uses 30; they are two different screens.
- Treating a period that includes today as final. Both Meta's lag and the fact that today is not over yet pull the numbers down.
- Reading "This month" as the whole month. It runs from the first of the month to today; the rest of the month has not happened.
- Trying to pick the comparison window by hand. It cannot be selected; it is always the equally long period immediately before.
- Expecting a custom range longer than 365 days. The limit is 365; go over it and the start is trimmed.
- Expecting the post list to change with the period. Post metrics are lifetime totals.
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