How the test works
Your browser is asked to fetch 36 scripts, the real ones websites load to show ads and track visitors. If something blocks a request — an extension, a browser’s built-in shield, or a DNS filter — it fails, and that script counts as blocked. The scripts are never run, and their responses are never read.
- Ad networks (10): Google AdSense, Google Ad Manager, Google Publisher Tag, Amazon Ads, Xandr (Microsoft), Taboola, Outbrain, Criteo, Media.net, Yandex Ads.
- Analytics (10): Google Analytics, Google Tag Manager, Microsoft Clarity, Mixpanel, Amplitude, Heap, HubSpot, Yandex Metrica, Quantcast, Comscore.
- Social pixels (9): Meta Pixel, X Pixel, TikTok Pixel, LinkedIn Insight, LinkedIn conversions, Pinterest Tag, Snap Pixel, Microsoft Ads (Bing), Reddit Pixel.
- Session recording (7): Hotjar, FullStory, LogRocket, Smartlook, Lucky Orange, Inspectlet, Crazy Egg.
A final check puts an invisible box with ad-like class names on the page. Blockers that also tidy the page, not just its requests, hide it — that’s what stops empty ad spaces and “disable your ad blocker” boxes from showing.
Why a blocker misses some
Blocking ads and blocking trackers are two different lists. Many blockers switch on the first by default — EasyList, for ads — and leave the second, EasyPrivacy, off. That’s how a browser can show no ads and still send your visit to a dozen analytics companies. Turning on the privacy list in your blocker’s settings usually closes most of the gap.
Chrome is its own case: it switched off older extensions in 2025, the original uBlock Origin among them. Its replacement, uBlock Origin Lite, works with fewer and more fixed lists, so a Chrome score that used to be perfect may not be now.
Blocking that’s built in
Brave, Firefox’s strict mode and Safari with a content blocker all block some of this without an extension. Tabula blocks it by default in every site you open: ad blocking and tracker blocking are on from the first launch, built from the same lists the best extensions use, and every site gets its own cookie jar — so a tracker that meets you in two windows sees two unrelated browsers. With its default settings, Tabula blocks all 36 scripts in this test. More on Tabula’s privacy.
Questions
Is the test safe to run?
Yes. Your browser asks each address for its script but never runs it, sends no cookies and no referrer, and nothing about the result is sent to us or stored. The companies behind the addresses see a request from your connection — exactly what happens on any site that uses them, which is most of them.
My ad blocker is on, so why is my score low?
Most often the blocker is paused on this site, or it only blocks ads and leaves trackers alone — many do by default. On Chrome, the original uBlock Origin was switched off in 2025 along with other older extensions; check that yours is still enabled. AdBlock Plus and AdBlock also let some ads through by default under their Acceptable Ads program.
Why does my score change between runs?
A request that takes longer than six seconds counts as blocked, so a slow or flaky connection can nudge the score up. Run it again on a steady connection and it settles.
What is a good score?
Ninety per cent or more means almost nothing that follows you around the web can load. Below sixty, most of the tracking gets through, even if you see fewer ads.
Does Tabula pass?
Yes — all 36, with its default settings, because ad and tracker blocking are built in and on from the start. Open this page in Tabula and run it to see.