Time Zone Converter
Convert a date and time between IANA time zones. See offsets, DST status, and weekday for both ends.
Enter input above to see the result.
What is this for?
Time zones are deceptively annoying. A meeting at "9am" means different absolute moments in London, Bratislava, and New York — and the offset between any two of them changes twice a year because of daylight saving, on different dates. This tool takes a wall-clock time in one IANA zone and tells you the exact equivalent in another, with current offsets, the UTC instant, and the day-of-week for both ends.
When to use it
- Scheduling a call across continents — confirming what "3pm CET" is in your colleague's zone without mental arithmetic or timezone-table hunting.
- Reading a log timestamp recorded in UTC and translating it to local time for a user-facing report or debugging session.
- Checking whether a deploy window, maintenance slot, or batch job crosses a DST boundary and might cause scheduling chaos.
- Sanity-checking that a cron expression in
America/New_Yorkfires at the moment you expect from your own zone. - Working out the day-of-week and date change when crossing the international date line or dealing with far-flung teams.
- Verifying timestamps in APIs, logs, or databases before storing or displaying them to users in their local time.
How it works
- Enter a date, time, and source IANA zone (e.g.
2024-03-15 14:30 Europe/London). - Pick a target zone from the dropdown or type to search ~400+ IANA zones.
- The tool instantly converts to the target zone, showing wall-clock time, UTC offset, DST status (standard or daylight), and day-of-week for both sides.
- The UTC row gives you the canonical absolute moment — the single instant both zones refer to.
- Adjust the source time and watch both conversions update in real time.
Why IANA zones (not "GMT+2")
An IANA zone like Europe/Bratislava or America/New_York encodes the historical and ongoing rules for that location — DST start and end dates, time-zone changes (Russia abolished DST in 2014; Türkiye dropped DST in 2016), even Samoa skipping a whole day in 2011. A bare offset like "GMT+2" tells you nothing about whether DST applies, what the rule was last year, or what it'll be next year. Browsers ship the IANA database (via ICU/CLDR) and update it automatically, so the conversion stays correct over time.
Common gotchas
- DST transitions create ambiguous and missing times. When a clock falls back, 02:30 happens twice; when it springs forward, 02:30 doesn't exist at all. The tool picks the standard-time interpretation by default; if you need the other side, shift by an hour either way.
- Offsets aren't constants. "CET" is UTC+1 in winter and UTC+2 in summer (CEST). The output always shows the actual offset for the date you entered, so trust the displayed offset over the abbreviation.
- Country abbreviations are not zones. "EST" is ambiguous (US vs Australian); "IST" can mean Indian, Irish, or Israeli. Always pick the IANA zone, not the abbreviation.
- Historical accuracy is good for the modern era but breaks down for very old dates. Pre-1970 timestamps may use approximated offsets in some browsers.
- Storing dates: always use UTC. Convert at display time. The UTC value in the output gives you the canonical moment to write to your database.