Why Ad Clicks Don’t Match Sessions in Google Analytics

You’re reviewing a recent digital ad campaign. It shows 510 clicks — great. Then you check Google Analytics for the webpage data, but it only shows 463 sessions.

Why is it less? Is one wrong?

This difference between clicks and “sessions” is common, frustrating and expected. And, since Google Analytics moved from Universal to GA4 in 2023, this gap has only widened.

At Zoe Marketing & Communications, we see this regularly. In our work with clients since 2020, we understand these discrepancies well — and why they aren’t a cause for concern.

In this blog, we’ll explain:

• The difference between clicks and sessions
• What a typical discrepancy looks like
• Changes brought by GA4
• 3 other factors that affect sessions
• The benefits of clicks and sessions

By the end, you’ll have a better grasp of why these numbers are different, why both are useful and what to do next.

The difference between clicks and sessions

In a nutshell, clicks (ad server data) measure how many total clicks your ad got. Sessions (Google Analytics data) count how many times the webpage you sent them to fully loaded.

Clicks

Clicks are straightforward. One click equals one click, regardless of whether the same person clicks multiple times or abandons the page. They're accurate, basic and usually higher.

Sessions

Google Analytics waits for the page to fully load before counting a session. It doesn’t register people who leave before that, and it only counts visitors within 30-minute windows. These factors are why sessions are usually lower than clicks — they're smarter and pickier.

What a typical discrepancy looks like

Your sessions will always be lower than your clicks — a 10% margin is normal. If you have 510 clicks and 463 sessions, that’s about a 9% difference, which is expected.

The ad-serving side tracks all departures, but not every arrival.

Changes brought by GA4

Since Google Analytics rolled out its new format, we see fewer session numbers, or “session starts.” Here’s why:

• UTM codes trigger fewer sessions in GA4
• Sessions no longer restart at midnight
• Multiple sources in a 30-minute window now count as one session
• GA4 has a more accurate session estimation

GA4 focuses more on engaged sessions (where people spend 10+ seconds on a page) and traffic sources.

3 other factors that affect sessions

You also might see discrepancies as a result of:

• Browser and security settings: Some people disable settings like images or JavaScript, so the page doesn’t fully load.
• Opt-out browser add-ons: Some users opt out of Google tracking.
• Tracking code setup issues: Improper tracking code can lead to fewer sessions being recorded.

Clicks vs. sessions: Why both matter

Sessions may seem like smarter data, but clicks offer valuable insights too.

What clicks tell us

Clicks show overall engagement and help gauge the effectiveness of your ad. Even if people don’t reach the landing page, they saw your branding and clicked.

What sessions tell us

Sessions show how many people made it to your page and are more likely to engage with you. Setting up a retargeting campaign for those who arrived is key to keeping them engaged.

Next steps for tracking metrics like a pro

Clicks and sessions are different, and that’s normal. You’ll generally see about 10% more clicks than sessions, and the gap may be wider with GA4.

Need help managing your campaign data? Talk to us. Zoe Marketing & Communications can help you grow your reach. What other campaign metrics should you track? Read on to learn more:

• The top general digital marketing metrics to track
• The most important metrics to track for sponsored content articles