Timezone Converter

2026-01-15T12:00:00.000Z is 2026-01-15T12:00:00+00:00 in UTC and 2026-01-15T07:00:00-05:00 in America/New_York.

How it works

• Read the input as an absolute instant, or resolved a bare wall clock using the source zone's offset for that date.
• Looked up the source and target zones' IANA rules for the instant through the runtime time-zone database.
• Rendered each zone's wall clock, UTC offset, abbreviation and daylight-saving state, then compared their calendar days.

• A daylight-saving gap (a local time that does not exist) is rejected rather than shifted.
• An ambiguous fall-back local time resolves to the earlier of its two instants.

Methodology

1. Read an ISO-8601 instant with an explicit offset as an absolute instant; otherwise interpret a bare date-time in the named source zone.
2. Resolve the wall clock to an instant using the runtime IANA database, rejecting nonexistent spring-forward times.
3. Render both zones with the offset, abbreviation and daylight-saving state that the IANA data reports for that instant.

Time model

• Time source: an explicit reference supplied by the visitor.
• Timezone: The input is either an absolute instant or a wall clock resolved in the named source zone; results are rendered in named IANA zones.
• Locale: No locale-specific formatting: wall clocks are ISO-8601 and offsets are numeric.
• Daylight saving: Daylight-saving transitions are resolved from the runtime IANA data, including nonexistent and ambiguous local times.
• Reference date: No implicit 'now': an instant or a local date-time with its source zone is required.

Usage

1. Enter an ISO-8601 instant with an offset (or Z), or a local date-time.
2. Choose the source IANA timezone.
3. Choose the target IANA timezone and read both wall clocks, offsets and the day shift.

Examples

These are examples, not current values: they use fixed inputs, while the interactive tool computes live results in your browser.

UTC to New York in winter

{
  "value": "2026-01-15T12:00:00Z",
  "from": "UTC",
  "to": "America/New_York"
}

UTC to New York in summer (DST)

{
  "value": "2026-07-15T12:00:00Z",
  "from": "UTC",
  "to": "America/New_York"
}

Local New York time to Kathmandu

{
  "value": "2026-01-15T09:00",
  "from": "America/New_York",
  "to": "Asia/Kathmandu"
}

Limitations

Instant versus wall clock

An instant is a unique point in time and can be written with an explicit offset like 2026-01-15T12:00:00Z. A wall clock such as 2026-01-15T09:00 is only meaningful together with a zone, which is why the source zone is required for bare local times.