# How to check your browser fingerprint > How to check your browser fingerprint: a uniqueness test says how rare it is, a consistency scanner whether it could be real. Run each twice. Source: https://mosaicbrowser.com/guides/check-your-browser-fingerprint ## How to check your browser fingerprint, and read the result Open a test page such as EFF's Cover Your Tracks or AmIUnique to see what a site can read and how rare it is, then a consistency scanner such as Pixelscan to see whether those values could belong to one real computer. Run each twice before you trust it. ![Two questions, two kinds of test page](https://mosaicbrowser.com/covers/check-your-browser-fingerprint.webp) To check your browser fingerprint, visit a page that reads it back to you. There are two kinds, and they answer different questions. Uniqueness tests such as EFF's Cover Your Tracks and AmIUnique tell you how rare your browser is. Consistency scanners such as Pixelscan tell you whether the values could belong to one real computer. Most people need both, and most guides only mention the first. ## Step 1: see what a site can read Open [Cover Your Tracks](https://coveryourtracks.eff.org/), the EFF's test, and press Test Your Browser. It says it "provides you with an overview of your browser's most unique and identifying characteristics", and it shows each value beside how common it is. [AmIUnique](https://amiunique.org/) does the same against its own collection of fingerprints. Its page is plain about the cost: pressing See My Fingerprint means "we will collect your browser fingerprint and we will put a cookie on your browser for a period of 4 months". What to look at in either one: - the User-Agent, and whether it names the browser and system you really run - screen size and pixel ratio - the WebGL vendor and renderer, which name your graphics chip - canvas and audio hashes - the font list - timezone and language If one of those is rare and you did not choose it (an unusual font you installed once, a high-contrast setting), that is the value that makes you easy to pick out. [What a browser fingerprint is](https://mosaicbrowser.com/glossary/browser-fingerprint) explains how a site turns each into an identifier. ## Step 2: check that it agrees with itself [CreepJS](https://abrahamjuliot.github.io/creepjs/) reads the same surfaces several ways, including from inside workers, and reports where the answers disagree. A browser whose page says one core count and whose worker says another has been modified, and CreepJS will say so. [Pixelscan](https://pixelscan.net/fingerprint-check) asks the question an anti-fraud system asks: could this be a real machine? It shows one headline, consistent or inconsistent, and cards for masking, automation and proxy use. Each card and our dated runs against it are in [what Pixelscan checks](https://mosaicbrowser.com/guides/what-does-pixelscan-check). Mosaic is a desktop app Email yourself the link and open it on your computer. [How it works: Its own Chromium](https://mosaicbrowser.com/features/engine) ## Step 3: check what leaks around a proxy If you browse through a proxy or VPN, run [BrowserLeaks' WebRTC test](https://browserleaks.com/webrtc) through it. It lists the public address WebRTC can find. If that is your home address and not the proxy's, every other setting is wasted. Then compare the browser's timezone with the location of your exit, because that is the first comparison a consistency scanner makes ([why the two disagree](https://mosaicbrowser.com/guides/browser-timezone-does-not-match-ip)). ## Step 4: run it twice, beside a control This is the step that separates a reading from a guess. A live scanner is a website having a good or bad day. In September 2026, on one Mac with no proxy, we ran an untouched Google Chrome through Pixelscan 20 times with a fresh profile each run. It was called consistent 16 times, masked 3 times, and returned no verdict once. A red result that a stock browser of the same version also gets is not a finding about you. So: 1. Run every test at least twice. A result that does not repeat is noise. 2. Run an untouched browser of the same version, from the same address, at the same time. 3. If your browser fails and the control passes, change one thing and run both again. The question that finds the worst faults is not "does it pass" but "does it pass twice". Our engine once had a geolocation spoof that answered the first request with the right coordinates and timed out on every request after it. Every manual test is a first request. ## How to read a browser fingerprint check | Result | What it means | What to do | | --- | --- | --- | | Unique on Cover Your Tracks or AmIUnique | A site can recognise this browser without cookies | Normal for most computers; matters for privacy, not for whether a fingerprint looks real | | Inconsistent on Pixelscan, control consistent | Something you changed contradicts the rest | Undo changes one at a time ([our list of causes](https://mosaicbrowser.com/guides/pixelscan-inconsistent-fingerprint)) | | Inconsistent on both | The site, or your address | Re-run later; try another exit | | WebRTC shows your home address | The proxy is being routed around | Fix that first | | Timezone in a different place from the exit | The clock and the network disagree | Match the zone to the exit | ## Checking a Mosaic profile In Mosaic you can run these pages from inside a profile's own browser, through its own proxy, without copying anything across. ![A pinned profile's actions menu in Mosaic: edit, leak test, warm up, unpin, duplicate, save as preset, move](https://mosaicbrowser.com/shots/pinned-profiles.png) *Run leak test and Check detectors sit in every profile's menu* 1. In the profile list, open the row's menu and choose **Check detectors**. 2. Pick a group: Consistency, Live gates, Leaks, Uniqueness or Automation. As of 2 November 2026 the catalogue holds 49 public detectors, including CreepJS, AmIUnique, Cover Your Tracks, Pixelscan, IPHey and the BrowserLeaks pages. 3. Pick a page. Mosaic starts the profile if it is not running and opens the page in a new tab of that profile's browser. 4. For the network half, choose **Run leak test** from the same menu. It checks from inside the profile's page that the exit address matches the proxy, that WebRTC shows no other public address, that the timezone, language and geolocation the page reads are the ones the profile claims, and that the timezone agrees with the exit's location. Nothing in the Check detectors dialog is scored by Mosaic; it shows what a pass looks like on that page, and you read the verdict yourself. The values those pages read are set inside [Tesseract Chrome](https://mosaicbrowser.com/features/engine), in C++, so the page, its workers and its iframes all report one machine. ## Sources 1. [EFF: Cover Your Tracks](https://coveryourtracks.eff.org/), read November 2, 2026 2. [AmIUnique](https://amiunique.org/), read November 2, 2026 3. [CreepJS](https://abrahamjuliot.github.io/creepjs/), read November 2, 2026 4. [BrowserLeaks: WebRTC Leak Test](https://browserleaks.com/webrtc), read November 2, 2026 5. [Pixelscan: fingerprint check](https://pixelscan.net/fingerprint-check), read November 2, 2026 ## Questions ### Is it safe to run a fingerprint test? The test pages read the same values any site reads. Some keep what they collect: AmIUnique says it stores your fingerprint and sets a cookie for four months when you press its button. Read each page's privacy note first. ### Why does my fingerprint test give a different result every time? Some values move on their own, such as window size and battery level, and some browsers add noise on purpose. Live scanners also disagree with themselves: an untouched Google Chrome on our Mac was called masked in 3 of 20 Pixelscan runs. ### Is a unique fingerprint bad? For privacy it means a site can recognise you without cookies. For an account it is normal, because almost every real computer is unique. What hurts an account is a fingerprint that contradicts itself. ### Can I check my fingerprint behind a proxy? Yes, and you should, because half of a consistency scan compares the browser's timezone and language with the location of the address it sees. A test without the proxy measures a different setup. ## Related [Browser fingerprint: what a site can read about your machine](https://mosaicbrowser.com/glossary/browser-fingerprint): A browser fingerprint is the set of values a site reads about your browser and computer, which together recognize you without cookies. What goes into one. [What does Pixelscan check?](https://mosaicbrowser.com/guides/what-does-pixelscan-check): Pixelscan checks whether a browser's fingerprint agrees with itself and with its IP, then names the card that failed. What each card reads, with our dated runs. [Browser timezone does not match IP: what it means and the fix](https://mosaicbrowser.com/guides/browser-timezone-does-not-match-ip): Browser timezone does not match IP? Your browser reads the computer's clock, and a proxy or VPN moves only the address. Match the zone to the exit. [How to change your browser fingerprint without breaking it](https://mosaicbrowser.com/guides/change-your-browser-fingerprint): How to change your browser fingerprint: change the whole machine at once. A single new value makes a browser rarer and contradicts the rest. [An anti-detect browser with its own Chromium engine](https://mosaicbrowser.com/features/engine): Mosaic is an anti-detect browser with its own Chromium engine, Tesseract Chrome: stock source plus 64 patches that change fingerprint values in C++.    ## Run this guide on your own accounts Every Mosaic profile is a fingerprint, a proxy exit and a cookie jar that agree with each other, kept on your computer. Free holds 3 profiles. Pro is $49 a month for any number. Mosaic is a desktop app Email yourself the link and open it on your computer.