TIME ZONE CONVERTER
Eight major zones are included: UTC, US Eastern, US Pacific, London, Central Europe, Dubai, Tokyo, and Sydney. They cover the bulk of business time-zone questions for North America, Europe, Middle East, and Asia-Pacific. Daylight saving is handled automatically for today’s date — for meetings far in the future, double-check around DST switch days.
Updated May 2026 · Built by Lukáš, an architect in Prague.
Formula, assumptions, rounding & limitations
Formula
UTC = source time − source offsettarget time = UTC + target offset- Offsets are looked up via the browser’s
Intl.DateTimeFormatAPI (IANA time zone database).
Assumptions
- The conversion always uses today’s calendar date in your browser’s clock.
- Daylight saving transitions are applied automatically based on each zone’s current rules.
- Time input uses 24-hour HH:MM format.
Rounding
- Conversions are exact to the minute. Seconds and milliseconds are not modelled.
Limitations
- Only eight major time zones are listed. For other cities, use a zone in the same area or a dedicated world-clock tool.
- Conversions for dates far in the future may be slightly off around DST transitions, because the lookup uses today’s date.
- Historical DST rules (years past) are not modelled by this tool.
Does it handle daylight saving time?
Yes. The browser’s Intl API knows when each zone switches between standard and summer time, so the conversion is correct on any date in the current year. The calculation always uses today’s date.
Why isn’t my city in the list?
We kept the list to eight major zones to stay simple. Most cities share a zone with a listed one (e.g., Berlin = Prague, Paris = Prague, Hong Kong ≈ Tokyo + 1h, Mumbai = Dubai + 1.5h). For full city coverage you can use a dedicated tool like timeanddate.com.
How do I figure out a meeting time across three zones?
Pick the source (your zone) and run the conversion to each target separately. There’s no three-way view here — that’s a different kind of tool, often called a “world clock” or “team scheduler.”
Why does the same time give a different result tomorrow?
Because the conversion uses today’s date. If a daylight saving change happens between today and the target date, the offset changes by one hour. For dates far in the future, double-check around DST switch days (March and November in most places).