What Your Browser Fingerprint Reveals (With Live Examples)

What fingerprinting actually is

Cookies used to be the main way websites followed you around. They're easy to block, easy to clear, and every browser has a setting for them. So trackers built something better: fingerprinting, which doesn't store anything on your machine. Instead, it reads signals your browser already exposes by design — screen size, installed fonts, the way your GPU draws a letter — and combines them into a stable identifier.

No single signal is a secret. Screen resolution, for example, is completely innocent on its own. But screen resolution + timezone + GPU model + the specific way your browser renders the word "mmmmmmmmmmlli" is almost certainly unique to you, your device, and nobody else in the world right now.

Entropy: the math of uniqueness

Fingerprinting is a numbers game. Each signal contributes some number of bits of entropy — bits of information that narrow down who you are. If a signal has 2 possible values, knowing yours eliminates half the population (1 bit). If it has 1024 possible values and yours is relatively rare, it might contribute 8–10 bits.

You need roughly 33 bits of entropy to uniquely identify one specific person out of 8 billion. A typical desktop browser leaks more than 30 bits through fingerprinting signals alone. That's why sites with good fingerprinting libraries can re-identify returning visitors with 99%+ accuracy even after a VPN change and a clear-cookies.

Let's walk through the biggest contributors.

Signal: Canvas rendering

const canvas = document.createElement('canvas');
const ctx = canvas.getContext('2d');
ctx.textBaseline = 'alphabetic';
ctx.fillStyle = '#f60';
ctx.fillRect(125, 1, 62, 20);
ctx.fillStyle = '#069';
ctx.font = '13px "Arial"';
ctx.fillText('FunWithText fingerprint', 2, 15);
const hash = sha256(canvas.toDataURL());
// "a7b3c9d2e1f8..." — stable per device, unique across devices

Signal: WebGL vendor & renderer

Vendor:   "Google Inc. (NVIDIA)"
Renderer: "ANGLE (NVIDIA, NVIDIA GeForce RTX 4070 Direct3D11 vs_5_0 ps_5_0, D3D11)"

Signal: AudioContext

Signal: Installed fonts

Signal: Hardware & display

Signal: Language & timezone

How to reduce your fingerprint

Fully blocking fingerprinting is hard — every signal you lie about is itself a signal (a trivially-spoofed UA + a canvas hash that matches Windows tells the tracker you're spoofing). The realistic goal is to look like a large herd: be one of millions of indistinguishable browsers, not one of a kind.

• Tor Browser is the gold standard. Every Tor user is forced into a small set of identical configurations (window size via letterboxing, fixed UA, fixed fonts, no WebGL details, no canvas).
• Brave has randomisation for canvas, audio, and WebGL built in via the "Shields" settings. Set "Block fingerprinting" to "Strict."
• Firefox — set privacy.resistFingerprinting to true in about:config. Breaks some video players and timezone display; survivable for most users.
• Don't install rare fonts. Every uncommon font adds entropy. Uninstall what you don't use.
• Use standard window sizes. Odd viewport dimensions stick out. Maximise, don't resize.
• Keep your browser updated. Old versions are rarer than new ones and therefore more distinctive.
• Avoid extensions that modify DOM globally (e.g. some "dark mode everywhere" extensions inject detectable style attributes).
• Use a separate browser profile for sensitive browsing. Fingerprints don't bridge across different browser processes if you're careful.

FAQ

What is browser fingerprinting?

A tracking technique that builds a stable identifier for your browser by combining low-level signals — screen size, GPU, fonts, timezone, canvas rendering, audio processing — into a single hash. Because no individual signal is unique but the combination is, fingerprinting works even when cookies are blocked.

Can I block fingerprinting?

You can reduce it, not fully eliminate it, in a normal browser. Tor Browser is designed so every user looks identical, which is the only way to be genuinely unidentifiable. Brave and Firefox offer strong anti-fingerprinting modes that degrade tracker accuracy substantially.

Is incognito mode enough?

No. Incognito prevents history, cookies, and cache from being saved locally. Every fingerprinting signal is identical in incognito and normal mode, so trackers see the same ID. A "new session" in incognito looks like the same browser to a fingerprinter.

How unique is my browser?

On a typical desktop, roughly 1 in 100,000 browsers share your exact fingerprint. On mobile it's better because devices are more uniform, but installed apps, fonts, and locale still produce millions of distinguishable profiles. Run our Fingerprint Check to see your own combined hash.

Does a VPN help against fingerprinting?

Not directly. A VPN changes your IP address but leaves every fingerprint signal untouched. A tracker that fingerprinted you once can still recognise you across VPN sessions. Use anti-fingerprinting settings and a VPN, not one or the other.