Time Zone Converter

How to use the time zone converter

1. Pick the date and time you know. It starts at the current time in your own time zone.
2. Choose its time zone in In this time zone and the zone you want in Convert to. Use ⇄ to reverse them, or Use current time to jump back to now.
3. Read the converted time, the number of hours between the two places, and whether the result falls on the next or previous day. The table underneath shows the same instant in nine other major cities, which is handy for scheduling a meeting across several countries.

The tool uses your browser's built-in time zone database (the IANA database), including each region's daylight-saving rules for the date you enter, so a summer meeting and a winter meeting can give different answers for the same pair of cities.

How time zone conversion works

Every time zone is defined by an offset from Coordinated Universal Time (UTC). To convert, the tool first turns the local time you entered into a single universal moment, then shows that moment as a local time in the other zone:

UTC time = local time − source offset target time = UTC time + target offset

The offsets are not fixed. Many places move their clocks by an hour for part of the year, so a zone's offset on 15 January can differ from its offset on 15 July. The converter looks up the offset that applies on the exact date and time you enter, for both zones.

Some offsets are not whole hours. India is UTC+5:30, Nepal UTC+5:45, and parts of Australia UTC+9:30 or UTC+10:30 during summer. Pakistan Standard Time is UTC+5 all year and has not used daylight saving since 2009.

Worked example: Karachi, London and New York

A call is set for 3:00 PM in Karachi (UTC+5):

• UTC time = 15:00 − 5 hours = 10:00 UTC.
• London in winter (GMT, UTC+0): 10:00 AM. In summer London is on British Summer Time (UTC+1), so the same 3 PM call is 11:00 AM.
• New York in winter (EST, UTC−5): 5:00 AM. In summer New York is on Eastern Daylight Time (UTC−4), so it is 6:00 AM.
• Tokyo (UTC+9, no daylight saving): 7:00 PM.

So the gap between London and New York is normally 5 hours. For a few weeks each spring and autumn it is 4 hours instead, because the United States and Europe change their clocks on different dates. Pakistan has no daylight saving, so the gap between Karachi and London is 5 hours in winter and 4 hours in summer, changing only when the UK changes its clocks.

Daylight saving time dates

Because the US and EU dates differ, the London–New York gap is 4 hours for about three weeks in March and again for a week in late October or early November, instead of the usual 5. Southern hemisphere places are on daylight saving during the northern winter.

Tips for scheduling across time zones

• Always write the zone with the time (for example 3:00 PM PKT or 10:00 UTC) so there is no guessing.
• Check the date, not just the hour. A late-evening time in Asia can fall on the previous day in the Americas.
• Use UTC as a neutral reference when working with servers and logs.
• Re-check a recurring meeting after each clock change, as the local time may shift for some attendees but not others.

Accuracy and limits

Conversions depend on the time zone data inside your browser, which is updated with the browser or operating system. Very old dates and far-future dates may use rules that governments later changed or have not yet decided. The list covers forty-odd widely used zones; a city not listed shares an offset with a nearby city in most cases. If a time falls into the hour skipped when clocks move forward, the tool warns you.

Frequently asked questions