Why do Unique Visitors differ between custom Table and Evolution reports?

When comparing custom Table and Evolution reports that share the same dimensions and metrics, the reported number of Unique Visitors may differ between the two reports. This is expected because of the way Matomo calculates unique visitors for each report type.

Report types

• Evolution report (time series): The report calculates unique visitors per period. A visitor who appears on multiple days will be counted once per day, then summed across the selected period.
  

• Table report (aggregated)
  The report shows the total count of Unique Visitors over the entire date range you selected. If a visitor appears on multiple days within that range, they are only counted once in the total.
  

Example

The following scenario is based on the date range 1-3 March.

• Visitor A visits on all 3 days (1-3 March).
• Visitor B only visits once (2 March).
• Table report: 2 unique visitors (A and B are each counted once across the date range).
• Evolution report: 4 unique visitors (Visitor A counted once per day = 3 and Visitor B counted once = 1).

This per-period counting can lead to a higher or lower total, depending on visitor behaviour. For consistent analysis, always compare Unique Visitor numbers within the same report type. It is recommended to use Table reports when you want the total number of Unique Visitors across a date range and Evolution graphs for understanding how unique visitors change over time, period by period.

The Custom Reports premium feature is included in Matomo Cloud plans. On-Premise users can purchase the premium feature on the Matomo Marketplace.