Look up a timezone offset and current local time

Resolve an IANA timezone to its UTC offset and local wall time at a specific instant.

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ToolTimezone Reference
Input
Output
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Preview

How it works

Intl.DateTimeFormat evaluates each chosen IANA zone at the supplied instant: longOffset yields its transition-aware UTC offset and date-time parts yield local wall time. The zone list is searchable text, but offsets are computed by the browser’s installed time-zone data rather than stored as fixed numbers.

  • Now is used only when no instant is supplied; an ISO timestamp with Z or an explicit offset makes the lookup reproducible.
  • The displayed names are a curated worldwide subset rather than all identifiers and aliases in tzdb.

Worked example

Tokyo
Search for a city, pinned to a known instant
Input
											Search: Tokyo
At: 2026-08-24T12:00:00Z
Output
												1 of 68 timezones match "Tokyo":

Zone        UTC offset  Local time      
Asia/Tokyo  UTC+09:00   2026-08-24 21:00

When to use this

Calendar invitations render one instant for attendees, schedulers preserve local civil time through daylight-saving changes, and UTC application logs are converted for support staff in named zones.

Edge cases

  • America/Denver and America/Phoenix can match in winter and diverge during US daylight saving, so each zone is evaluated at the selected instant.
  • Europe/Warsaw changes between winter and summer offsets; no year-round UTC number is attached to it.
  • 2026-08-24T12:00:00 has no zone designator and JavaScript interprets it in the browser’s local zone; use Z or ±HH:MM for portable results.

References