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Free Time Zone Converter

Convert times between any of 20 world time zones simultaneously. Use live current time or enter a custom date and time to compare.

Works offline once loaded
Selected time zones
New York
 
London
 
Tokyo
 
Sydney
 

Add a time zone

Common uses

  • Schedule Remote Team Meetings Across Time ZonesFind a meeting time that works for team members in multiple time zones simultaneously.
  • Convert Event Times for International AudiencesShow live event, webinar, or stream start times in attendees' local time zones to avoid confusion.
  • Plan Arrival Times and Calls While TravellingSee what time it is back home while travelling, or check local time at your destination for scheduling.
  • Track Global Stock Market Opening TimesConvert market opening and closing times for NYSE, LSE, TSE, and other exchanges to your local time.
  • Convert Game Release and Tournament TimesFind out exactly when a game releases or when an esports tournament starts in your local time zone.

How It Works

All conversion logic runs entirely in your browser using the JavaScript Intl.DateTimeFormat API — the same internationalization engine built into Chrome, Firefox, and Safari. There are zero external libraries and no server calls.

  1. 1
    IANA timezone list loaded
    On load, the tool calls Intl.supportedValuesOf('timeZone') to retrieve the full IANA timezone database your browser ships with — typically 400+ zones. On older engines it falls back to a built-in list of 20 major cities.
  2. 2
    Wall-clock input resolved to a UTC instant
    When you type a custom date and time, the tool runs a two-pass algorithm using Intl.DateTimeFormat(...).formatToParts() to compute the UTC offset for your chosen source zone, then subtracts it. A second pass re-checks the offset at the resulting instant to handle DST boundary edge cases correctly.
  3. 3
    Each target zone formatted independently
    Intl.DateTimeFormat is called once per selected timezone, passing the resolved UTC instant and the IANA zone identifier (e.g. Asia/Tokyo). The browser's built-in timezone tables handle DST rules and offset history, producing locale-aware weekday, date, and time strings.
  4. 4
    Live clock ticks via setInterval
    When 'use current time' is checked, a one-second setInterval updates the base date in React state, so every displayed timezone refreshes in real time. Your zone selections are saved to localStorage so they persist across visits.

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Frequently Asked Questions