Difference Wiki

CET vs. GMT: What's the Difference?

Edited by Aimie Carlson || By Janet White || Published on December 3, 2023
CET (Central European Time) is a time zone used in parts of Europe and Africa, 1 hour ahead of GMT (Greenwich Mean Time), which is the mean solar time at the Royal Observatory in Greenwich, London.

Key Differences

CET, or Central European Time, is the standard time zone for many countries in central Europe. GMT, or Greenwich Mean Time, is the time zone based on the mean solar time at the Prime Meridian in Greenwich, London.
CET is one hour ahead of GMT. This means when it is noon in the GMT time zone, it is 1 PM in the CET time zone.
During daylight saving time, CET becomes Central European Summer Time (CEST), which is two hours ahead of GMT. Conversely, GMT does not change during daylight saving time.
CET is used in countries like France, Germany, and Spain. GMT is no longer a standard time zone but serves as the basis for the UTC (Coordinated Universal Time) system.
CET aligns with Central Africa Time in some African countries. GMT is used as the standard time in countries like Iceland and is the same as Western European Time in countries like Portugal and the UK during the winter.

Comparison Chart

Time Difference

1 hour ahead of GMT
The base time zone from which others are set

Daylight Saving

Shifts to CEST, 2 hours ahead of GMT during summer
Does not change during daylight saving time

Geographical Use

Used in Central Europe and parts of Africa
Used in countries like Iceland, UK (winter)

Relation to UTC


Historical Context

Established for standardization in Central Europe
Historically the world's time standard, based at the Royal Observatory in Greenwich

CET and GMT Definitions


CET stands for Central European Time.
Meetings scheduled in CET are convenient for most European participants.


GMT served as the reference point for time zones around the world.
Time zones worldwide are expressed as positive or negative offsets from GMT.


CET shifts to CEST, Central European Summer Time, during daylight saving.
When CET moves to CEST, clocks are turned forward by an hour.


GMT does not change during daylight saving time.
Unlike British Summer Time, GMT remains constant throughout the year in the UK.


CET is synchronized with Central Africa Time.
Both Paris and Kinshasa share the same CET time zone.


GMT stands for Greenwich Mean Time, which aligns with UTC+0.
GMT is used as standard time in Iceland throughout the year.


CET is one of the key time zones in the European Union.
The European Central Bank in Frankfurt operates on CET.


GMT is the mean solar time at the Royal Observatory in Greenwich, London.
GMT was once the world's standard for civil time.


CET is the time zone observed in Central Europe, 1 hour ahead of GMT.
Berlin operates on CET, making it an hour ahead of London during winter.


GMT is equivalent to Western European Time during winter.
During winter, Lisbon time matches with GMT.


The local time at the 0 meridian passing through Greenwich, England; it is the same everywhere


What is CET?

CET stands for Central European Time, a time zone used in Central Europe and parts of Africa.

Which countries use CET?

Countries like France, Germany, Spain, and Italy use CET.

Does GMT observe daylight saving time?

No, GMT itself does not change for daylight saving time.

Is CET always one hour ahead of GMT?

Yes, CET is always one hour ahead of GMT, except during daylight saving time when it's two hours ahead.

How is GMT defined?

GMT is Greenwich Mean Time, based on the mean solar time at the Prime Meridian in Greenwich, London.

Is GMT still used today?

GMT is used in some places but has largely been replaced by Coordinated Universal Time (UTC).

Why was GMT chosen as the world's time standard?

GMT was chosen due to the location of the Prime Meridian at Greenwich, which was internationally agreed upon in 1884.

What is the difference between GMT and UTC?

GMT is based on solar time, while UTC is a more precise atomic time standard.

Do all European countries use CET?

No, not all European countries use CET. Eastern and Western European countries have their own time zones.

When does CET become CEST?

CET becomes CEST, or Central European Summer Time, during the summer months when daylight saving time is observed.

How does CET affect international meetings?

CET's time difference can affect scheduling for international meetings, especially with participants in other time zones.

Can GMT vary by a few seconds?

Yes, GMT can vary slightly due to the Earth's irregular rotation speed.

What is the purpose of daylight saving time in CET?

Daylight saving time in CET aims to make better use of daylight during the summer months.

Are GMT and British Summer Time (BST) the same?

No, BST is one hour ahead of GMT and is observed during summer in the UK.

Is CET affected by seasonal changes?

Yes, CET adjusts to CEST during the summer, moving clocks forward by one hour.

How do time zones like CET and GMT impact travel?

Travelers need to adjust their watches and schedules according to the time zone differences like CET and GMT.

Are there any global events scheduled in GMT?

Yes, some global events are scheduled in GMT to provide a common reference time.

Can CET and GMT be used interchangeably?

No, CET and GMT cannot be used interchangeably as they represent different time standards.

Why is GMT important in navigation and communication?

GMT provides a reference time for navigators and communicators across different time zones.

How do digital devices handle time zones like CET and GMT?

Digital devices often automatically adjust to local time zones like CET and GMT based on their location settings.
About Author
Written by
Janet White
Janet White has been an esteemed writer and blogger for Difference Wiki. Holding a Master's degree in Science and Medical Journalism from the prestigious Boston University, she has consistently demonstrated her expertise and passion for her field. When she's not immersed in her work, Janet relishes her time exercising, delving into a good book, and cherishing moments with friends and family.
Edited by
Aimie Carlson
Aimie Carlson, holding a master's degree in English literature, is a fervent English language enthusiast. She lends her writing talents to Difference Wiki, a prominent website that specializes in comparisons, offering readers insightful analyses that both captivate and inform.

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