Time Zone Converter Widget

Add a time zone converter to your website so visitors can turn a meeting, broadcast or deadline time into their own zone, and see the same moment in several other cities at once.

Time & Date Converter Runs in your browser Free · no ads

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Leave blank to use the widget's defaults. Visitors can still change every value.

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Exactly what your visitors will see

Embed code

<iframe src="https://a2z.tools/embed/w/time-zone-converter" title="Time Zone Converter by A2Z Tools" width="100%" height="600" style="border:0;width:100%" loading="lazy" allow="clipboard-write"></iframe>

A plain iframe. Works everywhere, including site builders that strip scripts. Adjust height if your content needs more room.

Works with

How it works

Pick a date and time, the zone it is written in and the zone you want. The widget finds the exact UTC instant for that wall-clock time using the shared A2Z date engine and the browser's IANA time-zone rules, then shows it in the target zone, in the source zone and in UTC, with the offset difference. Two cases are handled honestly: on the night clocks go forward, a time such as 02:30 does not exist, so the widget moves it forward by the size of the jump and tells you; on the night clocks go back, a time such as 01:30 happens twice, so it shows the first occurrence and names the second. Add extra zones to get a small table of the same moment around the world. The result also says when the converted time lands on the next or previous calendar day, which is the usual source of missed calls between Asia and the Americas. Offsets are always shown numerically (UTC+5:30, UTC-5) instead of as abbreviations, because IST means India, Ireland or Israel depending on who writes it and CST covers both Chicago and China. The zone list comes from the browser itself (Intl.supportedValuesOf), with legacy spellings such as Asia/Calcutta or Europe/Kiev shown under their current IANA names, Asia/Kolkata and Europe/Kyiv.

Method

  • UTC instant = wall-clock time - UTC offset of the source zone at that instant (found by testing candidate offsets)
  • Target time = UTC instant + UTC offset of the target zone at that instant
  • Gap (clocks go forward): the time does not exist; it is shifted forward by the change in offset
  • Overlap (clocks go back): two instants match; the earlier is shown and the later is reported

Worked examples

An India evening call for a New York client

Inputs: 2026-11-20 18:30 from Asia/Kolkata to America/New_York, also Europe/London and Asia/Tokyo

Result: Fri 20 Nov 2026, 08:00 in New York (UTC-5); UTC 13:00; London 13:00 (UTC+0); Tokyo 22:00 (UTC+9); difference -10h 30m

US daylight saving ended on 1 November 2026, so New York is on UTC-5 and 10 hours 30 minutes behind India. In early October the gap is 9 h 30 m.

A time that does not exist

Inputs: 2026-03-08 02:30 from America/New_York to Europe/London

Result: Sun 8 Mar 2026, 07:30 in London; New York shown as 03:30 (UTC-4) with a warning

US clocks jump from 02:00 EST to 03:00 EDT that night, so 02:30 is skipped; the converter moves it forward by the 60-minute jump, as a wall clock would.

A time that happens twice

Inputs: 2026-10-25 01:30 from Europe/London to Asia/Kolkata

Result: Sun 25 Oct 2026, 06:00 in Kolkata (first 01:30, BST, UTC 00:30); the note names the second 01:30 as 07:00 in Kolkata

UK clocks go back from 02:00 BST to 01:00 GMT, so 01:30 occurs at 00:30 UTC and again at 01:30 UTC.

Limitations

  • The tz database aims to be accurate only for timestamps since 1970; conversions for earlier dates may use simplified historical rules.
  • Minutes are the smallest unit; seconds in the input are ignored.
  • Only named IANA zones can be chosen; a bare offset such as UTC+7 or an abbreviation such as PST is not accepted as the source zone.
  • Future rule changes announced after the visitor's browser was built are not known until the browser updates.

Where publishers use it

  • Webinar and podcast pages where guests join from several countries
  • Remote-hiring and outsourcing agencies scheduling calls with clients abroad
  • Sports and esports sites announcing kick-off times for a global audience
  • Online course platforms with live classes across time zones

Questions

What if the time falls on a daylight-saving change?

If clocks jump forward past it (for example 02:30 on the US spring-forward night), the time does not exist and the widget treats it as the moment after the jump. If clocks go back and the time happens twice, it shows the first one and tells you when the second one is.

Where do the time-zone rules come from?

From the IANA time-zone database built into the visitor's browser, so rules stay up to date with browser updates.

Can I preset the zones?

Yes: v_from and v_to take IANA names (Asia/Kolkata, America/New_York) and v_extra takes a comma-separated list of up to ten more.

Why is Kathmandu 15 minutes different from India?

Nepal uses UTC+5:45 and India UTC+5:30. The converter handles 30- and 45-minute offsets exactly.

Sources

  1. Time Zone Database (tz / zoneinfo) - IANA . Offsets and daylight-saving transitions for every zone; read from the copy built into the visitor's browser
  2. ECMAScript Internationalization API Specification (ECMA-402) - Ecma International TC39 . Intl.DateTimeFormat time-zone formatting and Intl.supportedValuesOf('timeZone') for the zone list
  3. ISO 8601 date and time format - ISO . The YYYY-MM-DDTHH:MM input and the UTC line of the result

Cite or recommend this tool

If you reference this tool in an article, course or documentation, these formats are ready to copy. They are optional - nothing is added to your site unless you paste it.

A2Z Tools Time Zone Converter
https://a2z.tools/embed/time-zone-converter

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