TL;DR: Browser fingerprinting identifies you by combining small details about your device: screen size, fonts, time zone, browser version, settings and graphics quirks. Unlike cookies, you can't delete a fingerprint, and private or Incognito mode doesn't hide it. Google allowed fingerprinting by advertisers using its products from 16 February 2025, which the UK ICO called “irresponsible.” A tracker blocker plus a fingerprint-resistant browser such as Tor Browser or Brave helps most.

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What a browser fingerprint is

The EFF's Cover Your Tracks project describes a fingerprint as the set of traits that can single out your browser and hardware: screen resolution, installed fonts, time zone, browser settings, browser name and version, and more. Each detail is common on its own. Together they are often unique, so a site can recognise you across visits without storing anything on your device.

Advanced techniques add more signals. “Canvas” and WebGL fingerprinting ask your browser to draw hidden images; tiny differences in how your graphics hardware renders them add to the fingerprint.

Why it's harder to stop than cookies

If you want the cookie side covered too, see tracking cookies and Global Privacy Control.

Google's 2025 policy change

In December 2024 Google announced it would lift its ban on device fingerprinting for organisations using its advertising products, effective 16 February 2025. The UK Information Commissioner's Office called the decision “irresponsible,” as DLA Piper summarised, and issued guidance reminding firms that fingerprinting for ads still needs a lawful basis under UK rules.

What actually helps

  1. Use a tracker blocker such as EFF's Privacy Badger. It won't catch everything, but it blocks many fingerprinting scripts at the source.
  2. Choose a fingerprint-resistant browser. The EFF points to Tor Browser, which makes users look alike, and Brave, which randomises fingerprints. Firefox's stricter tracking protection also helps.
  3. Don't fake single traits. Changing only your browser version can make you stand out more.
  4. Test yourself at coveryourtracks.eff.org to see how unique your browser looks.

A VPN hides your IP address but not your fingerprint. Our guide to VPNs, browsers, email and messaging privacy explains what each tool does and doesn't cover, and is my smart TV spying on me shows similar tracking on other devices.

The bigger picture

Fingerprints let ad networks and data brokers link your browsing into a profile. That profile is another layer on top of the personal information already leaked about you. A free email exposure check shows which breaches your email appears in, and the full Scan My Shadow scan adds your phone number.

Frequently Asked Questions

What is browser fingerprinting?

A tracking method that identifies your browser by combining details such as screen resolution, fonts, time zone, browser version and settings into a profile that is often unique.

Does Incognito mode stop fingerprinting?

No. The EFF says private browsing mainly prevents local history storage, and Chrome’s Incognito offers no protection against trackers or fingerprinting.

Can a VPN stop browser fingerprinting?

No. A VPN changes your IP address but not the browser and device traits used in a fingerprint.

Which browser is best against fingerprinting?

The EFF points to Tor Browser, which makes fingerprints uniform, and Brave, which randomises them. Tracker blockers like Privacy Badger also help.

Is fingerprinting legal?

It depends on where you are. In the UK and EU, fingerprinting for advertising generally needs a lawful basis, and the ICO criticised Google’s 2025 change allowing it.

Sources

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