Fonts and Timezone: Two Quiet but Effective Fingerprints

When people think of fingerprinting, Canvas and WebGL come to mind first. But two quieter traits are often overlooked and surprisingly useful: installed fonts and timezone.

Font fingerprint

A page can use JavaScript to measure the width and height of the same text rendered in different fonts. By testing a long list of candidate fonts, it infers which fonts your system has. Your font set depends on your OS, system language, and the software you have installed (Office, design tools, font packs) — combined, it is quite distinctive.

Timezone fingerprint

The browser can read your timezone (e.g. Asia/Shanghai) via Intl.DateTimeFormat().resolvedOptions().timeZone with no permission needed. The timezone alone narrows down your region; more importantly, it is used for consistency checks: if your IP shows the US but your timezone is Asia/Shanghai and your language is zh-CN, a risk system flags you immediately as a likely proxy user.

Why they matter

Individually unremarkable, but stacked with other traits, fonts + timezone meaningfully raise uniqueness; a timezone/language that does not match your IP is the most common giveaway for proxy users.

How to reduce

• Do not install piles of rare fonts for looks — the more ordinary your system, the less you stand out.
• When using a proxy/VPN, keep your device timezone and system language consistent with your exit IP's region.
• Check your font list and timezone on our home page to gauge your exposure.