What is a browser fingerprint?

Every time your browser loads a page, it answers dozens of silent questions: What language do you speak? What screen size do you have? Which fonts are installed? What graphics card renders the page? What timezone are you in?

Individually, each answer is shared by millions of people. But the combination is rare — research by the Electronic Frontier Foundation found that most browsers have a unique fingerprint. A site can hash these values into an identifier that recognizes you even after you clear cookies or switch to incognito mode.

• Canvas and WebGL rendering — tiny differences in how your GPU and drivers draw graphics produce a unique image hash.
• User agent and browser version — your exact browser, version, and operating system.
• Screen and window size — resolution, color depth, and pixel ratio.
• Installed fonts and plugins — the set of fonts on your system is surprisingly distinctive.
• Hardware signals — CPU core count, device memory, touch support, battery status.
• Locale and timezone — language preferences and clock settings.
• Network details — your IP address, which also reveals approximate location and provider.

Fingerprinting has legitimate uses: banks use it to detect fraudulent logins, and sites use it to block bots. But it's also used for cross-site tracking and advertising — especially now that third-party cookies are being phased out. Because fingerprinting happens passively, it works even when you block cookies, and it's largely invisible to you.

Cookies are files stored on your device — you can see them, delete them, or block them. A fingerprint is never stored anywhere on your machine; it's recomputed from your browser's behavior on every visit. That's what makes it hard to escape: clearing your data doesn't change your screen size, GPU, or fonts.

• Use a browser with built-in fingerprinting protection, such as Tor Browser, Brave, or Firefox with strict tracking protection.
• Keep your browser window at a common size — unusual window dimensions are identifying.
• Limit extensions; each one changes your exposed environment.
• Use a VPN to mask your IP address and location.
• Prefer default settings — the more you customize, the more you stand out.

The goal isn't to hide completely — it's to blend in with the largest possible crowd of similar browsers.

The fastest way to understand fingerprinting is to see it in action. The BrowserSignals scanner reads the same signals trackers use, shows you exactly what's exposed, and estimates how many other browsers share your combination — plus AI-personalized tips to reduce your uniqueness.