IST to UTC Converter
Convert IST (Asia/Calcutta) to UTC (UTC), with daylight saving applied. Free, and runs entirely in your browser — nothing you enter is uploaded or stored.
About Timezone Converter
Enter a date and time, say which zone it is in, and see it in every zone you care about — plus an hour-by-hour strip showing where the working hours overlap. Leave the field empty to work from the current moment.
The strip covers a full day and scrolls, opening centred on the moment you asked about. The zone names stay pinned to the left while the hours scroll past, and every row uses the same columns, so reading straight down a column gives the same instant in each zone. Narrow the window to 12, 6 or 3 hours when a shorter view is easier to read.
Conversions use the IANA database in your browser, so daylight saving transitions are applied for the actual date rather than a fixed offset. That distinction matters: Europe/London is UTC in January and UTC+1 in July, and a hard-coded offset gets one of them wrong.
Where it helps
- Any number of target zones at once, which is what scheduling across teams actually needs.
- Daylight saving is applied per date, not as a fixed offset.
- The overlap strip makes a workable meeting slot obvious, across a whole day rather than a few hours around now.
- Local and offline — no calendar service involved.
Limits
- Zone rules come from your browser; an out-of-date browser may miss a recent change.
- Ambiguous local times during a DST transition — the hour that repeats in autumn, the hour that does not exist in spring — have no single correct answer.
- Abbreviations such as CST are ambiguous across regions, so IANA names are used instead.
- It converts moments; it does not check anyone's calendar or working hours.
Frequently asked questions
Why use America/New_York instead of EST?
EST is a fixed offset that is wrong for half the year, and several regions share the abbreviation. IANA names carry the full daylight saving history.
What happens to a time that falls in a DST gap?
It does not exist locally, so the result shifts to the nearest valid instant. Avoid scheduling anything between 01:00 and 03:00 on transition days.
How do I find a slot that works for three regions?
Add all three zones and read down the hour strip for a column where each row sits inside working hours.
Do the results account for a country changing its rules?
Yes, as far as your browser's data goes. Recent changes need an up-to-date browser or operating system.
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