Time Zone Converter
Convert a date and time between time zones using the IANA database, showing each zone's live UTC offset and whether the result lands on a different day.
2024-01-01 21:00 (+09:00)
Hour by hour across the day — pick the hour that suits everyone
Each row is one hour of the source day. Press a time to convert it.
- Working hours, 09:00–18:00, Monday to Friday
- Night, 22:00–07:00
- Weekend days are marked, taking Saturday and Sunday as the weekend — in several countries it is Friday and Saturday.
| UTC | Seoul | Working hours everywhere |
|---|---|---|
| 09:00 | ||
| 10:00 | ||
| 11:00 | ||
| 12:00 | ||
| 13:00 | ||
| 14:00 | ||
| 15:00 | ||
| 16:00 | ||
| 17:00 | ||
| 18:00 | ||
| 19:00 | ||
| 20:00 | ||
| 21:00 | ||
| 22:00 | ||
| 23:00 | ||
| 00:00 Tue | ||
| 01:00 Tue | ||
| 02:00 Tue | ||
| 03:00 Tue | ||
| 04:00 Tue | ||
| 05:00 Tue | ||
| 06:00 Tue | ||
| 07:00 Tue | ||
| 08:00 Tue |
Crossing zones without losing a day
Pick a date and time, choose the time zone it is written in, and choose the time zone you want it in. The tool instantly shows the same moment expressed in the target zone, along with each zone's UTC offset. It is built for the everyday questions that trip people up: what time is a 9am New York meeting for a colleague in Tokyo, when does a UTC deadline actually fall in Seoul, or how a flight's departure and arrival line up across regions. When the converted time lands on a different calendar day, a badge says which way and how far — “next day”, “previous day”, or “2 days later” where the date line puts the two zones further apart — so you don't schedule a meeting a day off. Swap the two zones with one click to convert in the opposite direction, and change any field to see the result update live. The answer also says when it lands at night, outside working hours or on a weekend; “Hour by hour across the day” lays the whole source day out in every zone you chose, and “Add to calendar” downloads the moment as an .ics event.
How the conversion works
The time you enter is treated as wall-clock time in the source zone. The tool finds the exact UTC instant that matches, then re-formats that instant for the target zone using your browser's built-in Intl time zone database. Because the calculation reads real IANA offsets, it naturally accounts for zones that sit at half-hour or 45-minute offsets, and for daylight-saving rules on the date you choose rather than a fixed guess.
Frequently asked questions
What time zone names should I use?
The dropdowns list common IANA zones such as UTC, America/New_York, Europe/London, and Asia/Tokyo. Using named zones (rather than a fixed offset) means daylight-saving changes are handled automatically for the date you pick.
Does it handle daylight saving time?
Yes. The offset is read from your browser's Intl time zone data for the specific date you enter, so a summer date and a winter date in the same zone can convert differently, exactly as they do in real life.
Can I convert to several time zones at once, or use a 12-hour clock?
Yes. Add as many target zones as you like — they travel in the share link too — and switch the clock to the 12-hour format if that is how you read time.
Can I find an hour that suits everyone, or put the time in my calendar?
Yes. Open “Hour by hour across the day — pick the hour that suits everyone”: each row is an hour of the source day, read in every zone you chose, with working hours and night shaded, weekend days named, and a ✓ on each row where every zone is in working hours. Press a row’s time to convert that hour. The answer and each extra zone also say when the time falls at night, outside working hours or on a weekend. “Add to calendar” downloads an hour-long .ics event set at that exact instant, so each calendar shows it in its own reader’s zone, with every zone’s time in its description.