Free tool
Ad Blocker Test: Check If Your Ad Blocker Is Actually Working
This test fires live requests at more than 100 real advertising, analytics and tracker domains, then reports exactly which ones your setup let through. It runs entirely in your browser and nothing is transmitted or stored.
Every tracker in this test loaded successfully. Nothing is blocking ads or trackers in this browser.
What this test actually measures
Most ad blocker tests show you a page with some ad-shaped boxes and ask whether you can see them. That measures cosmetic filtering, which is the weakest thing a blocker does. Hiding an element after it has loaded means the request already went out, the tracker already recorded your visit, and the bytes were already downloaded.
This test measures the thing that matters: whether the request leaves your browser at all. For each domain in the list, it issues a real network request and records whether the request completed or was cancelled. A cancelled request means the ad server never learned you exist. A completed request means it did.
How to read your score
The score weights network blocking at 80 percent and cosmetic filtering at 20 percent, because that reflects their real-world value. The breakdown underneath groups every domain by what it does, so a low score tells you specifically what is getting through: ad exchanges, analytics, session replay, data brokers or fingerprinting scripts.
| Score | Meaning | What to do |
|---|---|---|
| 95-100 | Effectively complete blocking | Nothing. This is working. |
| 85-94 | Strong, with a few gaps | Check which category is leaking below |
| 50-84 | Roughly half the ecosystem loads | Your filter lists are probably stale or limited |
| 1-49 | Minimal blocking | Your blocker is misconfigured or heavily restricted |
| 0 | Nothing is blocked | No blocker is active in this browser |
Why some rows say "blocked*" with an asterisk
A blocked request can fail in two different ways. A browser extension cancels it in-process, so it fails within a few milliseconds. A DNS-level blocker such as Pi-hole, NextDNS or AdGuard Home has to send the query to a resolver that either refuses it or drops it silently, which takes longer or times out entirely. Rows marked with an asterisk timed out rather than failing immediately, which usually indicates network-level rather than browser-level blocking. Our DNS blocking test separates these two layers properly.
What a perfect score does not prove
Domain blocking cannot stop an ad that is served from the same origin as the content. When a platform stitches the advertisement into the video stream itself, or renders sponsored content server-side into the HTML, there is no separate request to cancel. This is why YouTube ads can still appear for someone scoring 100 here, and it is a fundamentally different technical problem. We cover it in detail in server-side ad insertion.
The test also cannot see first-party analytics, where a site proxies tracking through its own domain specifically to evade filter lists. That practice is increasingly common and by design it looks identical to legitimate site traffic.
If your score is low
The most common causes, in order of frequency: no blocker is installed in this specific browser profile; the extension is installed but disabled for this site; filter lists have not updated in weeks; or the blocker is one of the products that operates an "acceptable ads" programme and is deliberately permitting a portion of the ad networks tested here.
ProBlocker blocks at the network level with no acceptable ads programme and no paid whitelist. Compare which blockers accept payment to unblock ads, or install ProBlocker and run this test again to see the difference directly.
Frequently asked questions
Is my ad blocker working?
Run the test above. It sends real requests to more than 100 advertising, analytics and tracker domains and reports which ones completed. If your blocker is working, most or all of them will be cancelled before they leave your browser.
What is a good score?
85 or above means your blocker is stopping the large majority of the tracking ecosystem. Between 50 and 85 means significant gaps. Below 50 means whatever you have installed is catching very little, and a score of 0 means nothing is blocking at all.
Why does the test say blocked when I have no ad blocker?
Something else in your setup is filtering. The usual causes are a Pi-hole or NextDNS resolver on your network, a VPN with built-in filtering, browser-level protection such as Brave Shields or Firefox Enhanced Tracking Protection, or corporate network filtering. Our DNS blocking test can help identify which layer is responsible.
Does a perfect score mean I will never see an ad?
No. This test measures domain-level request blocking, which is what stops the vast majority of web advertising. It cannot measure ads served from the same domain as the content, which is how YouTube server-side ad insertion and most sponsored content work. A perfect score here and an ad on YouTube are entirely consistent.
Does this test download actual ads?
No. It requests a small favicon path from each domain and only records whether the request completed or failed. No ad creative is fetched, no script from those domains is executed, and no result is transmitted anywhere. The whole test runs in your browser.