How to Convert Time Between Time Zones

UTC is the reference point

Every time zone is defined as an offset from Coordinated Universal Time (UTC). Tokyo is UTC+9, Nairobi is UTC+3, and New York is UTC−5 in winter.

To convert, first turn the local time into UTC, then apply the other zone's offset.

Worked example

9:00 AM UTC on January 15 is 9 + 9 = 6:00 PM in Tokyo the same day.

12:00 noon in New York on July 1 is 4:00 PM UTC (New York is UTC−4 in summer), which is 5:00 PM in London (UTC+1 in summer) — a 5-hour difference.

Daylight saving time changes the gap

The US and Europe switch clocks on different dates, so for a few weeks each spring and autumn the New York–London gap is 4 hours instead of 5. Many countries, including Kenya, Japan and India, don't use daylight saving at all.

That's why you should always convert for the specific date of the meeting, not a typical day.

Watch the date line

Converting across many hours can move the date. An evening call in Los Angeles is already the next morning in Sydney. Always check the day as well as the time.

Use zone names, not abbreviations

Abbreviations like CST or IST are ambiguous — IST can mean India, Ireland or Israel. Named zones such as Asia/Kolkata or America/Chicago are unambiguous and include each place's daylight saving rules.

The converter uses your browser's built-in time zone database, so it applies these rules automatically for the date you pick.