Erroneous count of unique visitors over a period

Support & Bugs
1

Hi there,

I notice a problem with counting unique visitors.

The number of unique visitors over a period is not identical to the cumulative number of unique visitors for each month.

I find 187,120 unique visitors when I take the figures month by month and when I select the whole period in Matomo, it calculates 174,471! Hello everyone,

I notice a problem with counting unique visitors.

The number of unique visitors over a period is not identical to the cumulative number of unique visitors for each month.

I find 187,120 unique visitors when I take the figures month by month (between September 2021 and June 2022) and when I select the whole period in Matomo, it calculates 174,471!

Which number is correct?

2

As far I can remember, the problem of changing unique visitors it’s because some of them belongs the month before (if you watch monthly). You only have this problem, watching yearly, for visitor sessions starting in dicember of previous year. :thinking: