What is CLS with adblocker on/off
CLS with adblocker on/off shows Cumulative Layout Shift (CLS) based on whether users have an ad blocker enabled. It compares real user experiences between ad-supported and ad-blocked visits.
This lens is helpful because ads are one of the most common causes of layout instability — especially if they load late, push content, or collapse after render attempts.
Only sessions where ad blocker status could be detected are included.
If ads shift content after the page starts rendering, it directly increases Cumulative Layout Shift. This can happen when:
Ad slots collapse after failing to load
Ads push content down when they appear late
Ad scripts delay layout stabilization
Users with ad blockers often skip these issues — which is why comparing both sides is useful.
Healthy CLS with adblocker on/off sample
If both ad blocker users and non-users show green CLS bars, your layout is stable across the board. That means you’ve successfully accounted for ad space and content order in your layout structure.
Unhealthy CLS with adblocker on/off sample
If CLS is worse for users without ad blockers, the most likely causes are:
Late-loading ad elements pushing the layout
Collapsible ad containers resizing after render
Scripts injecting content that shifts elements
Unreserved ad space causing content jumps
This leads to a jarring user experience, especially on mobile.
Resolving unhealthy CLS with adblocker on/off
Go-to action plan to resolve an unhealthy CLS with adblocker on/off:
Ask Uxi to analyze your CLS with adblocker on/off values and suggest improvements
Use Filters to isolate ad-heavy pages and measure which layouts shift most when ads load.
Simulate CLS of the suspected lens to see if fixing it will resolve the CLS with adblocker on/off. If yes, this is where the resolution focus should be.
Use an automated CLS optimization tool like Navigation AI to improve your CLS with adblocker on/off values
Once you’ve improved CLS, set an alert to be the first to know if it starts worsening again.
Try it yourself
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