Why is the sum of daily Returning visitors not the same as the total for the month?

Siteimprove Analytics shows figures for Visits, Page views, Unique visitors, and Returning visitors. A definition of these terms can be found in the article What do the different metrics (visits, page views, unique visitors, etc.) mean in Analytics? This article explains a commonly asked question on why the sum of daily Returning visitors is not the same as the total Returning visitors for the period of a month.

The daily Returning visitor numbers show the number of visitors on a day that also visited the site prior to the selected period. The monthly Returning visitor total shows the visitors who visited the site that month who have also visited the site prior to the selected period.

So, for example, a visitor can be registered as Returning visitor on both the first and second day of the month but for the total for the month, they are seen as one Returning visitor.

Returning Visitor example

Let’s use the figures shown in the table below for May 2020 as an example.

For all of May, there were 42,345 unique visitors of which 977 had also visited prior to May 2020.

On May 1st there were 157 returning visitors that also had a visit prior to the selected period (i.e. May 2020.)

On May 2nd there were 61 returning visitors that also had a visit prior to the selected period (i.e. May 2020).

Let’s say a visitor was on the website in April and then returned to the site on both May 1st and 2nd. In that case, the user would be counted as a Returning Visitor on both days individually (i.e. as seen on data points on the graph and in the table below) but only counted once for the full month period (i.e. as seen on the Monthly total number provided on the top of the Historical Comparison component).

You cannot compare daily numbers to monthly numbers when it comes to Returning Visitors and Unique Visitors. A visitor can be a unique visitor on every day of the month, but when aggregating the month figures the visitor is still one unique visitor.

Monthly totals

Daily Visits