Time Zone Detail

What is UTC ?

UTC (Coordinated Universal Time) conversion involves adjusting the time based on your location’s time zone offset from UTC. Simply add or subtract the number of hours from the current UTC time to get the local time.

  • Based on highly precise atomic clocks and adjusted with leap seconds to match the Earth's irregular rotation.
  • Adjusted periodically with leap seconds to account for variations in the Earth's rotation.
  • More precise due to atomic clocks, making it the international time standard.
  • The global standard for timekeeping, used in scientific, technical, and international contexts.
  • Introduced in 1972 to replace GMT as the international time standard due to its atomic precision.
  • UTC is the modern, more accurate global timekeeping standard.
  • Remains constant year-round, with no adjustments for Daylight Saving Time (DST).
  • UTC time conversion works by adding or subtracting a specific time offset based on the local time zone relative to UTC. Each time zone around the world is expressed as an offset from UTC, either ahead (+) or behind (-) UTC. For example:
    • UTC+1 means the local time is 1 hour ahead of UTC.
    • UTC-5 means the local time is 5 hours behind UTC.
What is GMT ?

GMT (Greenwich Mean Time) is the mean solar time at the Prime Meridian (0° longitude) in Greenwich, London. It was historically used as the global standard for timekeeping before being replaced by UTC (Coordinated Universal Time). GMT is still used in some regions, especially in the UK, during the winter months when Daylight Saving Time is not in effect.

Unlike UTC, GMT is based on the Earth's rotation and does not use leap seconds. It is often considered synonymous with UTC for practical purposes but lacks the atomic precision of UTC Although both GMT and UTC display the same time, there is a difference: GMT is now considered just a time zone officially used in some European and African countries. But UTC is not a time zone, but rather the new time standard that is the basis for clock time and time zones worldwide.

Difference between UTC and GMT :
Definition GMT is a time zone that was established based on the Earth's rotation and the position of the Prime Meridian (located in Greenwich, England). It was originally used for navigation and setting clocks. UTC is a time standard based on atomic clocks, providing much greater accuracy. It was introduced in 1960 to replace GMT for scientific and precise timekeeping purposes.
Accuracy GMT is based on the Earth's rotation, which can vary slightly over time. UTC is regulated by a series of highly accurate atomic clocks, which makes it more stable and reliable for precise timing needs.
Leap Seconds UTC incorporates occasional leap seconds to adjust for irregularities in the Earth's rotation. GMT does not account for leap seconds.
Usage GMT is mainly used as a time zone, especially in the UK during the winter months. UTC is a time standard and is used globally for synchronization across systems, scientific purposes, and aviation.