Timezone Converter

Scheduling a meeting between Mumbai and New York sounds simple — until you realise that the 9:30 AM slot in Mumbai is 11 PM the previous night in New York, and that offset shifts by one hour twice a year when the US observes daylight saving. Getting it wrong means missed calls, failed demos, and deals lost to a timezone error. This Timezone Converter handles the full complexity: 400+ IANA time zones, automatic DST handling for each zone on the exact date you enter, half-hour offsets like India and Iran, and a live world clock showing eight major cities updating every second.

Why the Date Field Is Critical for Accurate Conversion

Most people assume timezone conversion is just adding or subtracting hours. The trap: that offset changes for about half the world's countries twice a year due to daylight saving time. A New York meeting planned for “5:30 PM IST” on March 8 (before US DST starts) is at 7:00 AM ET. The same meeting on March 10 (after DST) is at 8:00 AM ET. The date field in this converter is not decorative — it tells the browser which DST rule to apply for both the source and destination timezone on that exact calendar date.

Countries With Unusual UTC Offsets

Most time zones are whole-hour offsets from UTC, but several widely used zones break that pattern:

• India (IST) — UTC+5:30, the world's most-used half-hour offset
• Iran — UTC+3:30 standard, UTC+4:30 in summer
• Afghanistan — UTC+4:30
• Nepal — UTC+5:45, the only country with a 45-minute offset
• Myanmar — UTC+6:30
• Australia/Lord Howe Island — UTC+10:30 standard, UTC+11 summer

All are supported correctly by the Intl API used in this converter.

The Live World Clock Panel

Below the converter, eight city clocks update every second showing the live local time, day, and date. This is useful for quickly checking whether someone is in business hours before placing a call — without having to enter a specific time for conversion. For a customisable board where you choose your own cities, the standalone World Clock supports 50+ cities with add/remove functionality.

Global Market Hours in Local Time

A frequent use case is checking when major financial markets open in your local time. Use the converter with From = the market's timezone and your local timezone as the destination:

• NYSE / NASDAQ — opens 9:30 AM America/New_York
• London Stock Exchange — opens 8:00 AM Europe/London
• Frankfurt (XETRA) — opens 9:00 AM Europe/Berlin
• Tokyo Stock Exchange — opens 9:00 AM Asia/Tokyo
• Bombay Stock Exchange (BSE) — opens 9:15 AM Asia/Kolkata
• Singapore Exchange — opens 9:00 AM Asia/Singapore

Technical Accuracy

The converter uses new Intl.DateTimeFormat('en-US', { timeZone: tz, ... }).format(date). The browser's built-in IANA timezone database contains every country's DST rules including historical changes. UTC offsets are read via timeZoneName: 'shortOffset' — so the GMT+5:30 label next to the India dropdown reflects the actual offset in use on the selected date, not a hardcoded label. For epoch timestamps in developer workflows, pair this with the Unix Timestamp Converter.

Privacy

The Timezone Converter runs entirely in your browser. No date, time, or timezone selection is transmitted to ToollyX servers. Safe for scheduling sensitive meetings, confidential board calls, and legal proceedings involving parties in different countries.