How to check your browser fingerprint, and read the result

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, 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 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 explains how a site turns each into an identifier.

Step 2: check that it agrees with itself

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 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.

How it works: Its own Chromium

Step 3: check what leaks around a proxy

If you browse through a proxy or VPN, run BrowserLeaks' WebRTC test 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).

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)
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.

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, in C++, so the page, its workers and its iframes all report one machine.