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.

What is the Timezone Offset Converter?

Free timezone offset converter. Enter a date and time at one UTC offset and instantly see the equivalent local time at any other offset, with the shared UTC instant shown for reference. Runs entirely in your browser. It runs free in your browser on Gera Tools, with nothing uploaded.

Timezone Offset Converter

Name: Timezone Offset Converter
Creator: Gera Tools
License: https://creativecommons.org/licenses/by/4.0/

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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.

When to use a fixed-offset converter

Most timezone tools work with named IANA zones (America/New_York, Asia/Tokyo) and automatically apply DST rules. This tool is intentionally different: it works with explicit UTC offsets only. That makes it the right choice when you already know the exact offset — because you read it from a log file, a calendar invite, or a timestamp header — and you want a quick arithmetic conversion without guessing what DST the named zone happens to be on that date.

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.

Worked examples

Example 1 — Meeting across time zones.
You have a call at 2026-06-06 09:00 in London during summer (UTC+1) and need the time in Tokyo (UTC+9):

Subtract source offset: 09:00 − 1h = 08:00 UTC
Add target offset: 08:00 + 9h = 17:00, same date
Result: Saturday 6 June at 17:00 in Tokyo

Example 2 — Late-night crossover.
A server in New York (UTC−4 in summer) logs an event at 23:30. What time is that in Singapore (UTC+8)?

Convert to UTC: 23:30 + 4h = 03:30 UTC, next day
Add target offset: 03:30 + 8h = 11:30, next day
Result: Sunday 7 June at 11:30 in Singapore

The date rolled because the gap pushed past midnight — the tool handles this automatically and displays the correct date at the target.

Non-whole-hour offsets

Not all time zones sit on whole hours. Common non-whole offsets include:

Region	Standard offset
India	UTC+05:30
Nepal	UTC+05:45
Iran	UTC+03:30
Afghanistan	UTC+04:30
Newfoundland (Canada)	UTC−03:30
Lord Howe Island (Australia)	UTC+10:30

All of these are selectable in the tool so you can convert to and from them without rounding.

Notes

This tool uses fixed offsets only and never guesses daylight-saving state. If a place is on summer time right now, select the offset it is actually observing — for example, choose UTC−4 for US Eastern in summer, not UTC−5. Everything runs locally; no times leave your device.