Time Zone Calculator
Enter your values below and click Calculate for instant results.
Convert any time between US and world time zones instantly. Shows the difference in hours and next-day notes.
Enter your values below and click Calculate for instant results.
Time zones divide the world into regions that observe the same standard time. The world is divided into 24 primary time zones, each roughly 15 degrees of longitude wide, corresponding to one hour of Earth's rotation. In practice, political boundaries cause many irregular adjustments, and some countries use half-hour or quarter-hour offsets.
The US spans six standard time zones: Eastern (UTC-5), Central (UTC-6), Mountain (UTC-7), Pacific (UTC-8), Alaska (UTC-9), and Hawaii (UTC-10). When it is noon Eastern, it is 9 AM Pacific. When it is 8 PM in New York, it is 1 AM the next day in London.
Most of the continental United States observes Daylight Saving Time from the second Sunday in March to the first Sunday in November. During DST, clocks are set forward one hour, effectively shifting each US zone to its summer offset (Eastern becomes UTC-4, Pacific becomes UTC-7, etc.). Arizona and Hawaii do not observe DST. This calculator uses standard (non-DST) offsets.
When scheduling meetings or calls with people in different time zones, always confirm the time zone explicitly rather than just saying "noon." Saying "noon Eastern" is unambiguous. Saying "noon" and assuming the other person knows your zone is a common source of missed calls and meeting confusion.