Difference between GMT and UTC
Greenwich Mean Time (GMT) and Coordinated Universal Time (UTC) are often used interchangeably and share the same current time in practice. But Greenwich Mean Time (GMT) and Coordinated Universal Time (UTC) are entirely different.
GMT is a time zone officially used in some European and African countries those lies near to prime meridian (longitude at 0 degree). GMT time is displayed in either 24-hour format or 12-hour format using AM and PM.
Coordinated Universal Time (UTC) is not a time zone, but a time standard that is used all over the world time zones to set their clocks. No country or territory uses UTC as a time zone. Time zones all around the globe are kept at hourly difference with Coordinated Universal Time (UTC).
For example; The time zone in India is called as Indian Standard Time (IST). Indian Standard Time (IST) is UTC+5:30. The meaning of UTC+5:30 is that, Indian Standard Time (IST) is 5 hours and 30 minutes ahead of Coordinated Universal Time (UTC). If the current Coordinated Universal Time (UTC) is 1:00, then the time at Indian Standard Time (IST) time zone is 6:30.
In other words, Greenwich Mean Time (GMT) is a time zone and Coordinated Universal Time (UTC) is a time standard. The GMT Time zone is kept at UTC+0:0. That means there is no "time zone based" time difference between GMT and UTC, but some European countries in GMT time zone use daylight saving of UTC+1 during summer.
Following are the countries in Greenwich Mean Time (GMT) time zone. Some countries apply daylight saving during summer.
Following countries in Greenwich Mean Time (GMT) time zone apply daylight saving of UTC+1 in summer.
• United Kingdom
• Portugal
• Ireland
• Faroe Islands
• Canary Islands
Following are the countries which use Greenwich Mean Time (GMT) all round the year, without applying daylight saving.
• Sierra Leone
• Mauritania
• Burkina Faso
• Iceland
• Saint Helena
• Gambia
• Ghana
• Guinea
• Guinea-Bissau
• Senegal
• Ivory Coast
• Togo
• Mali
• Sahrawi Arab Democratic Republic
• Liberia