Convert a specific date and time
- Enter the date and clock time in the source zone.
- Choose source and target zones. The date matters because offsets can change.
- Convert and review the UTC instant and both numeric offsets.
For example, 2024-01-01 at 09:00 in Asia/Kolkata is 03:30 UTC, or 2023-12-31 at 22:30 in America/New_York. Midnight crossings can change the target calendar date.
Skipped and repeated times
When clocks move forward, some local times do not exist. These are rejected rather than shifted silently. When clocks move back, some local times occur twice. The default asks you to select the earlier or later occurrence; the UTC instant identifies your choice.
In America/New_York, 2024-03-10 at 02:30 does not exist. On 2024-11-03, 01:30 occurs at both 05:30 UTC and 06:30 UTC. Changes need not be one hour: the converter uses the zone’s offset rules.
Time-zone data and limits
The searchable list includes named zones and legacy aliases from the documented IANA registry. Some names may be unavailable in an older browser; these are reported rather than substituted. Source dates from 1970 through 2100, with whole seconds. Output may cross into an adjacent year. It uses Luxon and your browser’s time-zone data. The IANA database changes as governments change their rules; browser data can lag updates. Check future schedules against the relevant local authority. This tool does not fetch or promise the latest database.
No abbreviation guessing (legacy names in the list are explicit IANA identifiers), leap seconds, other calendars, recurring meeting scheduling or elapsed-duration calculation. Inputs remain in browser memory; there are no uploads, saved dates or external conversion requests. CSV records the source, target, offsets and repeated-time choice. Undo action restores your date, time, both zones and occurrence choice before a shortcut, Swap, Convert back or Reset. Convert back uses the converted date and time as the new source and preserves the same UTC instant. It is available when that date falls within the supported source range.
Does selecting “later” fix a skipped time?
No. Earlier/later selects an occurrence only when a time repeats. A skipped time must be replaced with an existing local time.