Time Zone Calculator
Global Time Conversion & Synchronization
Converted Time Result
Your destination is 5 hours ahead of the origin.
* This calculator uses fixed UTC offsets and does not automatically account for local Daylight Saving Time changes.
Understanding Global Time Zones
UTC vs GMT
UTC is the atomic time standard used worldwide, while GMT is a historical time zone based on the prime meridian in Greenwich.
15° Rule
The Earth is divided into 24 segments. Every 15 degrees of longitude generally corresponds to a one-hour time difference.
Daylight Saving
Many countries shift their clocks forward in summer to better align daylight with active working hours.
The Foundation of Civil Time
A time zone is a region on Earth that uses a uniform time. These are typically based on political boundaries or lines of longitude. Coordinated Universal Time (UTC) is the high-precision standard today, based on atomic clocks rather than just the Earth's rotation.
UTC offsets range from UTC-12:00 to UTC+14:00. While most offsets are in whole hours, some countries like India (UTC+5:30) and Nepal (UTC+5:45) use fractional offsets for better solar alignment.
Fun Fact
Until 1929, most countries did not follow a standardized hourly time zone system. Local times were often set individually by towns based on when the sun was highest in the sky (local solar noon).
Global Time Zone Distribution
Global Time Zones Map
Standardized hourly offsets from UTC across the world. Time change of 1 hour is required with each 15° change of longitude.
Time Zones in the United States
The contiguous United States is divided into four primary time zones: Eastern, Central, Mountain, and Pacific. Including territories and non-contiguous states, the U.S. uses a total of nine time zones.
US Time Zones Map
Geographical distribution of the 9 time zones in the United States, including Eastern, Central, Mountain, and Pacific.
Daylight Saving Time (DST)
Often referred to as "Summer Time," DST involves advancing clocks by one hour in spring and rolling them back in autumn. The goal is to maximize daylight during waking hours and theoretically save energy. This practice is most common in North America and Europe, while many countries near the equator do not observe it because their daylight hours remain relatively constant year-round.
Daylight Saving Observance Map
Global distribution of countries and regions that observe Daylight Saving Time (DST).