Why not just add or subtract a fixed offset?

A fixed offset cannot express daylight saving. New York is UTC-5 in winter and UTC-4 in summer, so a fixed offset is wrong for half the year. Using the IANA database means the date itself determines which offset actually applied.

What does "this time does not exist" mean?

On the day daylight saving starts, local clocks jump straight from 02:00 to 03:00, so that hour never occurs in that zone. If you enter a time inside it, the tool flags it and shows the instant the clock jumps to instead of silently returning a wrong answer.

DATE AND TIME · CALCULATED IN YOUR BROWSER

Time Zone Converter

Convert one moment across several time zones with daylight saving applied automatically.

Enter a valid date.

Input

Source time zone

Date

Time

Compare with

Add a time zone

About this tool

Enter a date and time in one zone and see the matching local time, UTC offset, and zone name in every other zone you add — which is what scheduling across countries actually needs. Daylight saving comes from the IANA database rather than a hard-coded offset like "+8", so the answer stays right across the changeover. If you enter an hour that daylight saving skips, the tool says so instead of quietly returning something wrong.

How it works

Choose the source zone and enter the date and time.
Add the other zones you want to compare.
Read each zone's local time, offset, and whether the date shifts.

Assumptions

Uses the browser's built-in IANA time zone database so daylight saving is handled; fixed offsets are never used as an approximation.

Privacy

Every calculation runs inside this browser. Dates and birthdays are never uploaded, stored, or written to the URL or any log.

Frequently asked questions

Why not just add or subtract a fixed offset?: A fixed offset cannot express daylight saving. New York is UTC-5 in winter and UTC-4 in summer, so a fixed offset is wrong for half the year. Using the IANA database means the date itself determines which offset actually applied.
What does "this time does not exist" mean?: On the day daylight saving starts, local clocks jump straight from 02:00 to 03:00, so that hour never occurs in that zone. If you enter a time inside it, the tool flags it and shows the instant the clock jumps to instead of silently returning a wrong answer.

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