Browser Fingerprinting: How Sites Recognise You Without Cookies
Deleting cookies does not make you anonymous. Websites can also recognise your browser from the details it quietly reveals.
By Siddharth ShankarUpdated October 19, 2026Browser fingerprinting builds a profile of your browser and device from many small details, such as headers, time zone, settings, software versions, screen resolution and installed fonts. Unlike cookies, you cannot simply delete it. The Electronic Frontier Foundation says Tor Browser and Brave are designed to reduce fingerprinting, while Chrome Incognito offers no protection. Blocking tools help but cannot remove fingerprinting entirely.
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Most people know they can clear cookies to stop being followed around the web. Fingerprinting is the technique trackers use when cookies do not work.
What browser fingerprinting is
The Electronic Frontier Foundation’s Cover Your Tracks project explains that fingerprinting builds a profile of a browser and its hardware from many small details, so trackers can recognise it without stored files. Any one detail is common. The combination can be close to unique.
What details are used
- Information the browser sends to load sites, such as headers that show device and browser version.
- Your time zone, browser settings and installed software versions.
- Details gathered by tracking scripts, such as screen resolution and installed fonts.
How it differs from cookies
Cookies are files stored in your browser. You can block or delete them, which ends that tracking. Fingerprinting relies on hardware specifications and browser settings. EFF describes these as harder to change and impossible to delete. That is why clearing your history does not shake it.
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What protects you, and what does not
EFF’s page names several tools and their limits:
- Tor Browser is designed to reduce fingerprintability, so that your browser looks common and hard to tell from others.
- Brave randomises its fingerprint so a tracker cannot link you from one moment to the next.
- Privacy Badger and Disconnect block some fingerprinting domains, but not all.
- NoScript for Firefox reduces the data available to fingerprinters.
- Turning off JavaScript limits most fingerprinting data but breaks many sites.
- Firefox Private Browsing blocks trackers on a known list and known fingerprinters, but not new ones.
- Chrome Incognito gives no protection against trackers or fingerprinters.
The catch: protection can make you stand out
EFF warns that fully blocking trackers is difficult, and blockers do not stop more advanced techniques. Protections can also become part of your fingerprint. A browser that claims to be Chrome but behaves like Safari can stand out. That is why changing lots of settings by hand can backfire.
What you can do in practice
1Test your browser
Visit EFF’s Cover Your Tracks to see how unique your browser looks.
2Use a privacy-focused browser
Tor Browser and Brave are two named by EFF for reducing fingerprinting.
3Add a tracker blocker
It will not stop everything, but it reduces known trackers.
4Keep your setup ordinary
Avoid unusual extensions and settings that make your browser rare.
5Remember it is only one layer
Fingerprinting is not the only way you are tracked. Accounts, emails and phone numbers also link activity to you.
Why advertisers and others do it
Fingerprinting lets a company recognise the same browser across different websites and build a picture of what it does. It is also used for fraud detection, for example when a bank checks whether you are logging in from a device it has seen before. So not all fingerprinting is malicious, but the same technique can be used for tracking you without your knowledge.
How to read your test result
EFF’s Cover Your Tracks tool tests whether your browser blocks tracking and how unique it looks. A highly unique browser is easier to follow, which is why unusual extensions and settings can work against you.
Connect it to your wider footprint
Fingerprinting is passive tracking, part of what is called a passive footprint. See active and passive digital footprint examples and what metadata is. Check what your IP address reveals in what someone can do with your IP address.
Sources
- EFF Cover Your Tracks: Learn (definition, details used, differences from cookies, tools and limits)
Frequently asked questions
What is browser fingerprinting?
It is a way of recognising your browser and device from many small details, without using cookies.
Does clearing cookies stop fingerprinting?
No. EFF describes fingerprinting as harder to change and impossible to delete, because it relies on hardware and browser settings.
Does Incognito mode stop fingerprinting?
No. EFF says Chrome Incognito provides no protection against trackers or fingerprinters.
Which browsers help against fingerprinting?
EFF names Tor Browser and Brave as designed to reduce fingerprinting, but protection is never complete.
Can privacy tools make me easier to identify?
Yes. EFF notes that protections can become part of your fingerprint if they make your browser unusual.
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