Timezone Converter
Convert a time between any two time zones.
About Timezone Converter
The Timezone Converter takes a wall-clock time in one IANA time zone and shows the same instant in another — with daylight saving time handled correctly for the specific date, which is where mental arithmetic and hardcoded offsets fail. It answers both scheduling questions ("what is 15:00 in Mumbai for me?") and debugging ones ("this log says 02:14 in the server's zone — when was that for the user?").
Zones are real IANA identifiers (Europe/Berlin, America/New_York), not fixed offsets, so historical and seasonal rules apply automatically. A Swap button flips the direction for quick back-and-forth checks.
How to use
- Enter the "Date & time" as read on the wall clock.
- Choose the zone that reading belongs to in "From time zone" and the target under "To time zone".
- Click "Convert" to see the time in both zones plus the ISO 8601 UTC form.
- Use "Swap" to reverse the direction.
Frequently asked questions
Why use IANA zone names instead of offsets like UTC+2?
Because offsets change with daylight saving time and with legislation. Europe/Berlin is +1 in winter and +2 in summer; the IANA database encodes all of that per date, and this converter applies it for the date you enter.
Why do timezone bugs cluster around DST transitions?
On transition nights, one local hour either does not exist or occurs twice. Code that assumes every local time maps to exactly one instant breaks. Testing datetimes around the transitions in each supported zone is a high-yield strategy.
What zone should my backend store times in?
Store instants in UTC (or as Unix timestamps) and convert at the display layer. Systems that store local times without zone information create precisely the ambiguities this tool exists to untangle.