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About this tool
See the timezone, UTC offset, language list and formatting hints any website can read from your browser.
Timezone and Locale Fingerprint Viewer shows the location and language signals a website reads with no permission prompt: your IANA timezone, the UTC offset on today's date, whether that zone observes daylight saving, your ordered language list, and the calendar, numbering system and separators your locale resolves to. Offsets are calculated by formatting one instant in the zone and differencing it against UTC, so the value is the real current offset rather than a stored table. It also compares the timezone's country against the region in your language tag, the disagreement that a VPN typically produces.
Open Timezone and Locale Fingerprint Viewer on AltFTool — it loads instantly in your browser.
Add your input to the workspace.
Adjust the options until the result looks right.
Copy or download the output and put it to work.
The offset is derived from the zone on the current date, so daylight saving is reflected instead of assumed.
Flags when the timezone's country and the language tag's region disagree — the classic VPN tell.
Shows the same date and number rendered by your own locale, including the decimal and grouping marks.
Yes. Intl.DateTimeFormat().resolvedOptions().timeZone returns your IANA zone name, such as Asia/Kolkata, to any script with no prompt. Date.getTimezoneOffset() gives the numeric offset just as freely.
No. A VPN changes the IP address a site sees, but the timezone, language list and locale formatting still come from your device, so the two can point at different countries. Some privacy browsers spoof the timezone to UTC to close that gap.
Only three zones in the IANA database use a 45-minute offset — Nepal at +05:45, the Chatham Islands at +12:45 and Australia/Eucla at +08:45 — so the minute component alone places you in a very small group. Half-hour offsets like India's +05:30 narrow the field less sharply but still considerably.
Yes. Browsers send the language list as the Accept-Language HTTP header on every request, so its content and order reach the server without any JavaScript running. Trimming the list in browser settings is what changes it.