There could be a various number of reasons why Piwik numbers are different from your other web analytics solution.

  • Identifying Visitors: Piwik uses a javascript based tracker, and keeps count of unique visitors using a first party uuid cookie, as well as a visitor recognition heuristics algorithm (based on IP address and user settings). Some other tools only use cookies, only use IP, or a combination: we found that the way Piwik tracks visitors gives us really good accuracy and avoids creating artificial visits.
  • Tracking method: Other softwares (such as AWStats, Webalizer, Analog, etc.) or custom server-side script would record all traffic, including search bots or spam bots. Check that you are comparing Piwik with a similar web analytics tool
  • Bots and Spiders tracking: By default Piwik uses a Javascript tracker which automatically only records “real” human activity and excludes all bot activity. This leads to more accurate reports. If you compare Piwik to Google Analytics and notice a large discrepancies (over 5%) you may try to disable bot tracking in GA. To do this in Google Analytics go to Admin settings and navigate to View Settings under the View panel. Find the checkbox “Exclude traffic from known bots and spiders” and select it. Then both Piwik and Google Analytics will exclude all bot traffic. (PS: Piwik can be configured to enable tracking of search engine bots).
  • Hits vs Visits: Log analyzers softwares will typically report “hits”. Hits generally count all http requests to your websites: pages, images, css, javascript files, etc. Piwik reports page views, unique visitors, visits, etc. whiLogs analyzersch are expected to be much less than the number of hits.
  • Record loaded page: when the Piwik javascript code is located at the end of the page, Piwik will only record page views for page that are finished loading. Log Analyzers would also record page requests that have been “cancelled”, eg. when the user hits the Back button before the page is displayed.
  • Position and presence of Javascript tag: when comparing Javascript-based statistics (eg. number of unique visitors), you have to make sure that both javascript tags are present on all pages you want to track. Also, it is better to put all tracking codes at the end of your pages, just before the </body> tag.
  • DoNotTrack support: Piwik by default respects the DoNotTrack setting. If visitors have selected not to be tracked in their browser, Piwik will not collect information about them. If you suspect many of your users are using DoNotTrack, you can disable it in the Privacy settings.

Concerning Google Analytics, several users compared Piwik and Google Analytics numbers, and found very similar statistics: on significant traffic, differences were always less than 5 percent.

Conservative counting is definitely best – it makes your statistics more realistic on what you are trying to measure. Most analytics packages are used to measure relative upswings, we recommend using the same tool for all measurements and relative comparisons.

See also the FAQ: Piwik tracks a lot less visits than other web analytics tools, but tracks the same number of pageviews.