How does converting between offsets work?

Every wall-clock time corresponds to one absolute instant in UTC. The tool subtracts the source offset to get UTC, then adds the target offset to get the destination time. Conversion is just arithmetic on minutes.

Why does the date sometimes change?

When the offset difference pushes a time past midnight, the calendar date rolls forward or backward. For example, 11 PM at UTC+9 is 2 PM the same day at UTC+0, but 6 AM the next day at UTC+12 may land on a different date.

Does this handle daylight saving time?

No. This tool works with fixed numeric UTC offsets, not named zones. If a region is observing DST, pick the offset it is currently using (for example UTC-4 instead of UTC-5 for US Eastern in summer).

What offsets are supported?

Any offset from UTC-12:00 to UTC+14:00, including half-hour and 45-minute offsets such as +05:30 (India) and +05:45 (Nepal). You select offsets directly so there is no ambiguity from named zones.

Is my data sent anywhere?

No. All conversion happens in your browser using local date arithmetic. Nothing is uploaded, stored, or logged.

Timezone Offset Converter

Take a date and time at one UTC offset and convert it to the equivalent wall-clock time at any other offset. The tool also shows the shared UTC instant, so you can see that both local times point to the same moment.

How it works

Wall-clock times only make sense relative to an offset. To convert, the tool reduces the source time to UTC and then re-expresses it at the target offset:

utcMinutes   = sourceTime - sourceOffset
targetTime   = utcMinutes + targetOffset

Offsets are stored in minutes (so +05:30 is +330, −04:00 is −240). The whole calculation is integer arithmetic on a timestamp, after which the timestamp is broken back into a date and time. When the result crosses midnight, the displayed date rolls forward or backward automatically.

Example

You have a meeting at 2026-06-06 09:00 in London during summer (UTC+1) and want the time in Tokyo (UTC+9):

Convert to UTC: 09:00 − 1h = 08:00 UTC.
Add the target offset: 08:00 + 9h = 17:00, same date.
Result: 2026-06-06 17:00 at UTC+9.

Notes

This tool uses fixed offsets, not named timezones, so it never guesses about daylight saving rules. If a place is currently on summer time, choose the offset it is actually observing. India (+05:30) and Nepal (+05:45) are included because their offsets are not whole hours. Everything runs locally — no times leave your device.