What is my timezone?
No prompt was involved in reading the zone above, and it is a place name rather than a number of hours. That makes it one of the quietest location leaks on the web: a VPN moves your IP to another country while your browser keeps announcing the timezone you actually live in, and the mismatch is itself a signal.
Your timezone and current offset from UTC are shown above. Your browser knows this from your operating system's clock settings and exposes it to any page through the Internationalization API, no permission required. It is given as an IANA name like Europe/Amsterdam or America/New_York, plus your live offset.
The IANA name is more useful than a raw offset because it encodes the daylight-saving rules for your region, so a site can display correct local times all year without guessing. Your offset alone (say UTC+1) is ambiguous, since many places share it at different times of the year.
This is one of the few location-adjacent signals a site can read silently, without a prompt, which makes it a quiet but reliable hint about where in the world you are.
How a website reads this
This is the exact call a page makes. Nothing else is involved, and nothing is sent anywhere: the value is read in your browser and displayed to you.
Intl.DateTimeFormat().resolvedOptions().timeZoneReturns an IANA zone name such as "Europe/Amsterdam", read silently with no prompt. It is a stronger location hint than most people expect, because the zone name is a place name, not merely an offset from UTC.
- Needs your permission
- No, it is read silently
- Can it be faked
- Yes. Change your system timezone and it changes. Firefox's resistFingerprinting reports UTC to every site, and Tor Browser does the same.
- Contribution to a fingerprint
- About 3 bits, our own estimate. Our estimate. There are a few hundred IANA zones but they are used very unevenly, so a common zone is cheap and a rarely used one is unusually revealing. How we estimate this.
What you should know
Why sites collect it
Sites use your timezone to show times, schedules and deadlines in your local clock, to pick sensible defaults for bookings and calendars, and to time notifications. It saves you from doing timezone maths by hand.
Privacy implications
Timezone is a moderate fingerprinting signal. It does not pinpoint you, but it narrows your region, and combined with language and IP it sharpens a location guess. Because it needs no permission, it is a favourite passive signal for tracking scripts.
How to change or hide it
Your timezone follows your OS clock setting, so changing that changes what sites see, though it also changes your own clock. Some privacy browsers can report a fixed timezone (often UTC) to reduce distinctiveness. There is no per-site prompt because it is not treated as sensitive.
Frequently asked questions
How does the site know my timezone without asking?
It reads the timezone from your operating system clock through a standard browser API. This needs no permission because it is treated as low-sensitivity, unlike GPS location.
Why is my timezone shown as a city name?
The IANA format uses a representative city, like Europe/Amsterdam, because it captures the region's daylight-saving rules, not because you are in that exact city.
Sources
Browser behaviour changes and vendors cap these values differently, so the claims above that are not self-evident are checked against the specifications and vendor documentation below.
Last checked on . How these values are measured and estimated is set out on the methodology page.
Something wrong here? Tell us what your browser reports and it gets corrected.