Ads slow page loads, take up screen space and sometimes carry trackers that follow you across sites. An ad blocker extension filters out known ad and tracker requests before they load, which speeds up browsing and removes most banner, video and pop-up ads without changing how a site otherwise works.
How an ad blocking extension works
An ad blocker checks each request a page makes against filter lists of known ad and tracker domains, then blocks the ones that match before they load. This is why blocked pages often feel faster: fewer images, scripts and trackers are downloaded in the first place.
Ad blocker extensions and Manifest V3
Chrome's Manifest V3 rules changed how ad blockers can filter requests, moving many of them to a built-in filtering system with a capped number of rules. Extensions built specifically for Manifest V3, rather than adapted from older versions, tend to handle this limit more reliably.
When you don't need an ad blocker extension
Some sites rely on ad revenue and ask you to disable blocking or subscribe instead, and blocking everything everywhere can occasionally break a site's layout or video player. Most ad blockers let you pause blocking on a specific site, which is worth doing for sites you want to support directly.