Time zone converter
Turn a wall-clock time in one IANA zone into the same instant in another, including daylight-saving gaps.
Runs locally in your browser. Nothing is uploaded.
How to convert a time
Pick the wall-clock date and time, then choose the zone that clock belongs to and the zone you want to read. The result is the same instant, printed in the destination zone with its short abbreviation. A meeting at 16:00 in Asia/Kolkata is 10:30 in UTC, because India is five hours and thirty minutes ahead of UTC and does not observe daylight saving. The same 16:00 in America/New_York is a different UTC instant in January than it is in July.
Use an IANA name such as America/Los_Angeles or Europe/London. Abbreviations like IST, PST, and CST are ambiguous: IST can mean India, Israel, or Ireland, and CST is used in both North America and China. If the zone you need is not in the short list, type its IANA name in the extra field. The browser already ships the zone database through the Intl API, so this page does not download a timezone file and it does not ask a server what time it is.
Open “This instant in other zones” after a conversion when you are lining up a call. The table shows one instant in each listed zone. Share the UTC time when the group spans several regions, then let each person read that instant in their own zone.
Daylight saving, gaps, and overlaps
Some zones skip an hour in spring and repeat an hour in autumn. A local time that falls in the spring gap does not exist. The converter tells you so instead of silently picking a neighboring hour. A local time in the autumn overlap happens twice. The result uses the earlier instant and lists the later one as well, so you can see both offsets. UTC itself never shifts. Asia/Kolkata does not either. America/New_York, America/Chicago, America/Denver, America/Los_Angeles, and Europe/London do.
The fields of a cron schedule are also wall-clock fields. If you are explaining a schedule on the cron expression explainer, choose the zone the server uses, which is often UTC, and read the next runs there. A clock time with no zone is not an instant. This page’s job is to attach the zone and produce the instant.
Common questions
Why is there no separate page for IST to PST?
One converter covers every pair. Choose Asia/Kolkata as the source and America/Los_Angeles as the destination. PST is the winter abbreviation for that zone; in summer the same zone is PDT, one hour further from UTC. Naming the IANA zone keeps the answer right on both sides of the change.
Does the page know about future rule changes?
It uses the time zone data in your browser. When governments change daylight-saving rules, browsers ship the update in a later release. The page does not keep a private copy of the database that could go stale on its own.
What if I only know the offset, such as UTC+5:30?
A fixed offset is not a zone. UTC+5:30 matches Asia/Kolkata today, and it also matches other regions that do not share India’s history. Prefer the city or region name. Use UTC when you truly mean a zero offset with no daylight saving.
Is the time I type sent anywhere?
No. Formatting is done with Intl.DateTimeFormat in the page you already loaded. The date never leaves the browser, and the page does not call a time service.