Notes

Google &num=100 change: The reason why your GSC impressions fell overnight.

Article — If you’ve noticed a sudden GSC impressions drop but clicks look steady, don’t panic. Google appears to have disabled the &num=100 search parameter that let people load the top 100 search results in one hit. Let's dive into the impact this has had for reporting and rank tracking tools.

Posted by
15.09.2025
What's in the article:

What changed and when?

SEO news outlets and community threads report that around 10–12 September 2025, Google started ignoring &num=100. Many SEOs also saw desktop impressions tumble around the same window. At the time of writing, Google hasn’t posted an official announcement, but the behaviour change is consistent across tests and reports.

Why impressions fell but clicks didn’t?

Here’s the key: Google’s own documentation says an impression is counted when your result appears on the current page of results — even if it isn’t scrolled into view (unless it’s in a widget that needs expanding). If a bot or tool loaded a page that contained 100 results, your listing could rack up impressions without a human ever seeing it. Once &num=100 stopped working, those artificial impressions evaporated — so impressions drop, average position improves, and clicks stay stable. That’s exactly the pattern many are seeing.

Why desktop performance took the hit

Most rank tracking runs on desktop SERPs, so the desktop line in GSC tends to show the biggest swing when scraping behaviour changes. Industry write-ups noted the drop was particularly visible on desktop impressions last week.

Gsc impressions down

Are rank tracking tools “broken”?

Some are, temporarily. Tools that relied on &num=100 need to re-engineer how they collect results (for example, using traditional pagination via start=…, throttling, or alternative data sources). You might see gaps or oddities in tracking until vendors roll out fixes. Even third-party SERP APIs have reported inconsistencies when requesting 100 results recently, hinting at a broader shift.

What this tells us about past rank tracking data

The scale of the drop has surprised many — in some properties, impression totals halved overnight. That suggests a non-trivial share of impressions came from automated loads by SEO tools rather than real people. It also helps explain earlier debates of a ‘zero-click phenomenon’ where impressions rose but clicks lagged: if tools inflated impressions, click-through rates would look worse than reality.

Gsc impressions drop 1

What you should do this week (owner-friendly checklist)

Reset your reporting baseline

  • Split GSC by Device → Desktop and compare 7–14 days before vs. after 10 September 2025.
  • Note the new normal for impressions, average position and CTR; annotate all reports from this week so future you (and your team) don’t misread the dip.

Validate that traffic is fine

  • Cross-check Google Analytics (or your analytics platform) for clicks/sessions from Google. If clicks are steady, you’re dealing with a measurement change, not a demand problem.
  • Use Google’s definition of impressions to explain to stakeholders why drops can occur without traffic loss.

Patch your rank tracking

  • Ask your vendor how they’re handling the num=100 change and when stability will return.
  • Until then, lean more on GSC query/page reports for directional rank views and on actual clicks for performance decisions.

Communicate clearly

  • In your marketing report, add a short note such as: “Google disabled &num=100 in mid-Sept. This removed bot-driven impressions from GSC, especially on desktop. Clicks and revenue are unaffected.”
  • Keep referencing the official impression rules if you get pushback on why the position improved while impressions fell.

What this means going forward

  • Cleaner GSC data: With fewer tool-triggered loads, your impression numbers should better reflect real people.
  • Less noisy CTR: Expect CTR to lift slightly as the denominator (impressions) normalises.
  • SERP volatility continues: Google has tested several SERP changes in 2025; keep an eye on how pagination and AI surfaces evolve, as they can change what counts as an impression.

Get fewer surprises and clearer reports

If you’re a hands-on owner and want steadier dashboards, simpler reporting, and proactive alerts when Google SERP changes 2025 roll through, partner with a digital agency that lives in this stuff daily. We’ll reset your baselines, tighten your tracking stack, and focus on the metrics that move revenue. Reach out and let’s turn this week’s “dip” into cleaner, smarter decision-making — fast.

Get a FREE Digital Marketing Audit

References

Reporting on &num=100 being disabled/tested

Deep-dive analysis and data examples

Official documentation to explain impressions and position behaviour