Winter: 09:00 New York becomes 23:00 Tokyo
Input and settings
2024-01-15 09:00:00 America/New_York → Asia/Tokyo
Expected result
Tokyo: 2024-01-15 23:00:00 UTC: 2024-01-15T14:00:00.000Z
Time Zone Converter
Convert a local date and time between IANA time zones with daylight-saving rules.
How to use
- Enter the source date and time.
- Choose the source and destination time zones.
- Review the result, including any change to the previous or next date.
Enter values
Conversion result
Convert an announcement to Japan time
Example: 2026-09-14 10:00 UTC becomes 19:00 in Japan on the same day. ISO dates with Z or a numeric UTC offset are also supported.
About this tool
The converter uses the browser's Intl implementation and IANA zone names, with no external timezone API.
Nonexistent local times during a daylight-saving jump are rejected. Results depend on the timezone database included with your browser, which may be outdated in an old browser.
Convert an announced UTC time by choosing a city or region
2026-09-20T09:00:00Z is 09:00 UTC. Choose Tokyo as the destination and the result is 18:00 in Japan. A trailing Z or numeric offset in the input supplies the source zone.
- Choose a city or region such as Tokyo or Europe/London. Ambiguous abbreviations such as CST are rejected because they can refer to different zones.
- Historical and future daylight-saving results depend on the browser’s time-zone data. Confirm critical deadlines with the organizer’s published zone.
Try a use case and check the result
Convert the same 09:00 New York clock time to Tokyo on fixed winter and summer dates. These dates are not the current time.
Example buttons replace the inputs and settings above and calculate. Restore previous input steps back one example at a time. After trying multiple examples, repeat restore to return to your original input. This history is lost when the page closes.
Summer: the same 09:00 becomes 22:00 Tokyo
Input and settings
2024-07-15 09:00:00 America/New_York → Asia/Tokyo
Expected result
Tokyo: 2024-07-15 22:00:00 UTC: 2024-07-15T13:00:00.000Z
How to read the result
Input is the source region’s local date and time. On these two dates New York changes from UTC−5 to UTC−4, so the difference from Tokyo changes from fourteen to thirteen hours. Specify both region and date, then check the destination date and UTC line. Displayed date formats and zone abbreviations vary by browser.
Scope and limits
Conversion uses the browser’s Intl zone data and seconds 00–59. Local times missing at a daylight-saving transition are rejected. When a clock time occurs twice in autumn, the tool returns one occurrence without an earlier/later selector. Check the UTC result and verify ambiguous appointments using an explicit offset. Future regional rule changes depend on device data updates. These examples leave the announcement-text input untouched.
Verification: existing functions are checked for winter 14:00Z, summer 13:00Z, rejection of a missing time and the UTC result for a repeated time. Browser checks in UTC, New York and Tokyo compare conversion and input restoration.
Continue with the next task
Choose the matching input method
For conversion between cities, use the upper form to select a date, time, source zone and destination zone. The announced-time field accepts a date and time containing UTC, JST, Z or a numeric UTC offset and converts it to Japan time. Its destination is fixed to Japan time.
Inputs and copying
Entered dates, times and announced date-times are not autosaved. The announced-time result is copied to the clipboard when you press Copy result.
Frequently asked questions
Does it handle daylight saving time?
Yes. It uses the browser's IANA rules for the selected date.
Does it call an external API?
No. Conversion uses Intl on your device.
What is an ambiguous local time?
When clocks move back, one local time can occur twice. The tool displays one valid interpretation chosen by the browser-based conversion.
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Inputs and storage
Keep any content you need before clearing. This tool does not autosave inputs or results. Reloading or closing the page, clearing inputs or resetting may discard your work.
Favorites and language preferences are stored separately and may be lost when site data is cleared. Tool resets and site-data deletion do not delete files already downloaded to your device.