Ad Blockers Explained: What They Do and How to Set One Up for Free

An ad blocker is a browser extension that prevents most online advertisements from loading when you visit websites. This includes banner ads, pop-up windows, video ads that play automatically, and those tracking scripts that follow you across the internet to show you targeted advertising.

Using a good ad blocker has several real benefits. Pages load noticeably faster because the browser no longer has to download dozens of ad images and scripts. The visual experience is less cluttered. Certain types of malicious advertisements — sometimes called "malvertising" — that attempt to install malware or redirect you to scam pages are blocked before they can load. This last benefit is particularly important for safety.

Ad blockers work by checking each piece of content a website tries to load against a list of known ad servers and trackers. If the content comes from a known advertising source, the blocker stops it from loading. These block lists are maintained by communities of researchers and are updated regularly.

The most trusted free ad blockers are uBlock Origin (available for Chrome, Firefox, and Edge) and AdGuard AdBlocker. Both are free, open-source (meaning their code is publicly visible and audited), and have been independently reviewed as safe and effective. uBlock Origin is particularly well-regarded because it uses very little of your computer's resources.

Some websites detect ad blockers and ask you to disable the blocker before reading their content. Whether you choose to do so is up to you — many people whitelist websites they want to support (like local news sites) while keeping the blocker active on other sites.