When Google Analytics GA4 counts different sessions than Universal Analytics, it confuses many website owners. GA4 defines sessions differently from its predecessor system. This means a direct comparison of session numbers is not meaningful. In this post about different GA4 session counts, we explain the technical differences. We show you how to properly contextualize the new numbers.

Why Does GA4 Count Different Sessions Than Universal Analytics?

In Universal Analytics, a new session started at midnight, with new campaign parameters, and after 30 minutes of inactivity. GA4, however, does not start a new session at midnight or with new campaign parameters. The 30-minute timeout remains the same though. This results in GA4 generally counting fewer sessions than Universal Analytics. Also check the new bounce rate in GA4, which is also based on sessions. Both metrics are directly connected.

How Big Are the Differences in Practice?

Typically, GA4 counts 10 to 20 percent fewer sessions than Universal Analytics. For websites with high nighttime traffic, the difference can be larger since the midnight rule no longer applies. Furthermore, campaigns with many UTM parameters lead to greater discrepancies. However, GA4 provides more accurate user data by avoiding artificial session splits. The Google documentation on data differences confirms these discrepancies.

Our Recommendation

Do not compare GA4 session numbers directly with old UA data. Instead, use GA4 data as your new baseline. GA4 session counts are more accurate since artificial splits at midnight and campaign changes are eliminated. Therefore, only perform historical comparisons within the same system. Additionally, we recommend focusing on users and engagement rate rather than sessions alone.

Conclusion

GA4 systematically counts fewer sessions than Universal Analytics. The new counting method is more precise and avoids artificial session splits. Our Google Ads agency helps you interpret GA4 reports correctly. Also read our post about discrepancies between GA4 and Google Ads numbers.