# Is your ad blocker actually working? > A free, safe test to find out if your ad blocker really works. It checks ads and trackers across 50+ real services, including the telemetry of Xiaomi, Samsung, Oppo, Huawei and Apple phones. It also shows which DNS you're using. Works with uBlock Origin, AdGuard, Pi-hole, NextDNS and Brave. No data collected: the test runs entirely in your browser. Free in-browser tool (no upload): https://www.mauriziofonte.it/tools/adblock-test Press one button and find out in seconds whether your browser is protected. We check if ads and trackers get stopped, and tell you in plain words what's working and what isn't. **We load no real ads and collect no data**: everything happens in your browser. ## How the test works 1. **The test starts on its own** - As soon as you open the page we try to load the real scripts of about 30 advertising and tracking services (Google Ads, Facebook, Google Analytics and many more), plus 25 telemetry endpoints of Xiaomi, Samsung, Oppo, Huawei and Apple phones: 50+ real probes in total. If the script loads, that service **passed**; if your browser blocks it from loading, it's **stopped**. We never initialize the scripts, so they send no data. 2. **Stopped or passed** - If the request can't leave, that service is **stopped** by your blocker. If it goes through, it **passed**. That's how we measure how effective your protection is. 3. **Checking the empty slots** - We drop fake ad boxes into the page (which you never see) and check whether your blocker hides them. This is the test that tells a browser extension apart from a network blocker. 4. **The result, in plain words** - We give you two separate scores (ads stopped and empty slots hidden) and tell you, in plain words, what kind of blocker you have and what you can improve. The *What slipped through* list shows you what to add. ## Why two scores and not just one Almost every test like this hands you **a single score**. That's a mistake, because ads get blocked in two different ways, and knowing this helps you pick the right tool. **First way: stop the ads before they arrive.** Your blocker keeps the browser from connecting to the sites that serve ads. It's the most effective approach, and when you use a network blocker (like Pi-hole or NextDNS) it protects every device in your home, not just the browser. That's the score on the left. **Second way: hide the leftover boxes.** Sometimes the ad loads anyway and an empty box is left behind. Browser extensions (like uBlock Origin) can hide it; a network blocker can't, because it never sees the page. That's the score on the right. The upshot: a Pi-hole user will have a low score on the right, and **that's not a problem**: it's simply a tool that works differently. By giving you two separate scores, this test tells you the truth about what you're running and where it's worth improving, instead of one number that just muddies the picture. ## Glossary - **Ad blocker**: A tool that stops ads and trackers from loading while you browse. It can be a browser extension or a blocker that works across your whole home network. - **Tracker**: Small pieces of code that follow what you do online (which pages you visit, what you click) to build a profile and show you targeted ads. A good blocker stops them along with the ads. - **uBlock Origin**: The most recommended ad-blocking extension: free, lightweight and effective, for Chrome, Firefox and Edge. Be careful not to confuse it with the many clones that have similar names. - **Pi-hole**: A small "filter" you set up at home (often on a Raspberry Pi) that blocks ads for every device on the network, including TVs and phones. It can't hide the empty boxes on pages. - **NextDNS / AdGuard DNS**: Services that block ads and trackers at the network level, without installing an extension. A few settings and they protect every device. Like Pi-hole, they don't hide empty slots. - **Acceptable Ads**: A feature, on by default in Adblock Plus, that lets some ads deemed "non-intrusive" through. It's the most common reason for a only-partial score. It can be turned off in the extension settings. - **Empty slot (ad box)**: When an ad is blocked but its empty box is left behind on the page. Browser extensions can hide it; network blockers can't. - **Brave**: A browser with ad and tracker blocking built in (called Brave Shields). No extension needed: it protects against both connections and empty slots. ## Frequently asked questions ### Do I have to score 100%? No, and it's worth knowing. We deliberately include a few new or niche services: even great protection lets some through. What matters is understanding how you're protected and closing the important gaps shown in *What slipped through*, not chasing a full score. ### I use Pi-hole and the right-hand score is zero: is it broken? No, it's completely normal. A network blocker like Pi-hole stops ads before they load, but it can't hide the empty boxes on pages because it never sees the content. Only a browser extension does that. If you also want to hide the empty slots, add uBlock Origin. ### Does the test load real ads or spy on me? To tell whether your blocker works we load the real ad-network scripts, exactly as any website would: it's the only reliable way to know if they get blocked. But we **never initialize them** (no `ga('create')`, `fbq('init')` or ad slots), so they send no tracking data and you see no ads. Most importantly: we **send nothing to our servers**, build no profiles, and there are no ads on this page. Everything stays in your browser. ### I have uBlock Origin but something shows as "passed": why? Usually for two reasons: the service is new and not yet covered by your lists, or uBlock made it harmless by replacing it with an empty version (so to us it looks "passed" but in practice it does nothing). The *What slipped through* list tells you which addresses you can add. ### Does it work with AdGuard, NextDNS, Brave? Yes. With NextDNS or AdGuard DNS you'll see a high score on the left and a low one on the right (they're network blockers). With Brave, which builds blocking into the browser, you'll see high scores on both. The test recognizes on its own what kind of blocker you're using. ### My score is only partial, what am I doing wrong? The most common causes: "acceptable ads" enabled by default in Adblock Plus (turn it off in settings), out-of-date blocklists, or a weak extension. The advice: switch to uBlock Origin with the default lists, or add a network blocker for the whole home. ### Can I use the result to improve my protection? Yes, it's one of the goals. The *What slipped through* section lists the addresses that loaded, with a button to copy them; you can add them to your extension or your Pi-hole/NextDNS. Below you'll also find the full list of every tested service. ### Do you also test phone telemetry (Xiaomi, Samsung, Oppo)? Yes. In the *Phones & devices* section we check the addresses that phones and smart TVs (Xiaomi, Samsung, Oppo, Huawei, Apple, OnePlus, Realme, Roku) use to send data to their makers. The browser never contacts them, but the test checks whether your blocker would cover them: this is most useful with a network blocker like Pi-hole or NextDNS. We verified one by one that these addresses really respond, so we don't give you false "stopped" results. We show it separately because a browser extension can't block them. ### How reliable is the result? Very, because we use the same real addresses that blocking programs actually check. On a very slow network a service can occasionally show as "stopped" just because the response was late: if in doubt, press *Run it again* on a stable connection. ### Is my data safe? Yes. The test runs entirely in your browser: no result is sent to our servers, we build no profiles, and there are no ads on this page. It's a tool built for your privacy, not against it. --- Tool by Maurizio Fonte, senior backend engineer. All tools: https://www.mauriziofonte.it/tools/