You have heard of cookies. You probably know to clear them occasionally or use incognito mode. But there is another tracking technique that ignores all of that — one that works even in incognito mode, even after clearing cookies, and even if you have never signed in to the website you are visiting.
It is called browser fingerprinting, and it is far more difficult to block than cookies.
What Is Browser Fingerprinting?
Browser fingerprinting is a technique that identifies you by combining the technical characteristics of your browser and device into a unique "fingerprint." Instead of storing a tracking ID in a cookie on your computer, the website calculates an ID from information your browser automatically shares with every site you visit.
These characteristics include your browser type and version, operating system and version, installed fonts, screen resolution and colour depth, timezone and language settings, installed browser plugins, hardware specifications (number of CPU cores, GPU model), how your browser renders canvas graphics and WebGL scenes, audio API characteristics and dozens more signals.
Each of these signals is relatively common. But combined together, the specific combination is often unique — like a fingerprint. Research shows that browser fingerprints are unique for roughly 83–95% of users, meaning most people can be identified even without cookies.
Why Is It Harder to Block Than Cookies?
Cookies are stored on your computer. You can delete them, block them, or use private browsing to prevent them from persisting. Fingerprinting requires no storage on your device — it works by reading information your browser makes available to every website by design. Blocking it means either lying to websites about your browser characteristics (which can break sites) or blending in with millions of other users by making your browser look identical to everyone else.
How to See Your Own Fingerprint
Our free Browser Fingerprint Checker shows you the exact signals your browser exposes — canvas fingerprint, WebGL data, fonts, screen resolution, audio fingerprint and a uniqueness score based on how distinctive your combination is.
You can also check our Browser Privacy Score for a full assessment of how trackable your current setup is.
Who Uses Browser Fingerprinting?
Ad networks — to track users across sites without relying on third-party cookies, which are being phased out. Fingerprinting is increasingly replacing cookies for cross-site tracking.
Banks and financial institutions — to detect fraud. If your bank sees your account accessed from a device with a very different fingerprint, it may flag the login as suspicious.
Large publishers and e-commerce sites — to identify returning users for personalisation, even after they clear cookies.
Analytics companies — to measure unique visitors more accurately than cookies alone allow.
How to Reduce Your Fingerprint
Brave browser is the most effective option — it randomises fingerprinting signals on each site visit, making it impossible to track you consistently across sessions. This is called "fingerprint randomisation" and is built in by default.
Firefox with the Resist Fingerprinting setting (privacy.resistFingerprinting in about:config) reports standardised values for most fingerprint signals, making you look like a large pool of Firefox users rather than an individual.
Tor Browser is the gold standard for fingerprinting resistance — all Tor users have identical fingerprints by design. The trade-off is significantly slower browsing.
uBlock Origin does not block fingerprinting directly but blocks the tracking scripts that read fingerprint data. Combined with a privacy browser, it significantly reduces tracking.
Can You Block It Completely?
Not entirely — some fingerprinting signals are inherent to how the web works. The goal is to be as similar to other users as possible (large anonymity set) rather than unique. Running a mainstream browser in a standard configuration with fingerprinting protections makes you much harder to track than someone with a heavily customised setup, which paradoxically makes them more unique.
