By default, unique visitors metric KPI is processed for days, weeks and months. The “Unique Visitors” metric can be found under “Visitors > Overview” in Matomo. When you view a “Day” report, you can also find a “Unique Visitors” column in most reports (for example the number of unique visitors who reached your website from a specific Website Referrer). It is not possible to get the “Unique Visitors” column for reports other than “Daily” reports.

However if you are looking at getting the overall “Unique Visitors” metric for Years and Custom Date Ranges, this can be enabled on request. (By default for performance reasons the “Visitors > Overview > Unique Visitors” metric is disabled because the SQL query to process the number of unique visitors is quite costly and takes seconds or even minutes to run on a High traffic Matomo (Piwik) server.)

You can decide to enable or disable the unique visitors metric for specific periods by adding the following in your config/config.ini.php:

[General]
enable_processing_unique_visitors_day = 1
enable_processing_unique_visitors_week = 1
enable_processing_unique_visitors_month = 1
enable_processing_unique_visitors_year = 0
enable_processing_unique_visitors_range = 0

By default, unique visitors are processed for days, weeks and months (they are set to 1). You can for example enable yearly unique visitors by setting enable_processing_unique_visitors_year = 1

Important notes:

More information about unique visitors

The number of unique visitors across the month is processed by calculating the number of distinct visitors looking at the logs for the whole month.

When you select a date range, by default there is no unique visitors metric processed by default. And if you sum up the daily unique visitors metric you will not get the total unique visitors across the date range: this is because one visitor may visit the website on several days, and when you sum a number of uniques per day you will end up counting the same visitor multiple times. Therefore to get the number of unique visitors accurately across a date range period, you cannot sum the number of uniques for the sub-periods within and must enable this feature.

Note: This document is written in an assumption that you’re using On-Premise Matomo, if you have any question regarding Matomo Cloud, please contact our Support team.