What is the difference between GMT and UTC?

UTC is the same time of GMT. GMT means Greenwich Mean Time at UTC+0, and UTC means Coordinated Universal Time at UTC+0.

Which time zone does this page use for GMT?

Etc/GMT. An abbreviation is not a time zone — it is a label a zone wears for part of the year — so every calculation here uses a named IANA zone and says which one. If you are writing code, use Etc/GMT rather than the string "GMT".

Does GMT mean anything else?

Yes: United Kingdom local time in winter at UTC+0. Britain is on GMT only from late October to late March; the rest of the year it is on BST, an hour ahead.

Is GMT a daylight saving abbreviation?

No. GMT is the standard-time abbreviation. When daylight saving is in force, the same zone uses a different one.

GMT to UTC

GMT sits at UTC+0; UTC sits at UTC+0. That puts UTC the same time of GMT.

Convert a time

From

Date

Time

Converted time

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The converter needs JavaScript to run. Everything below — offsets, daylight saving dates and the hour-by-hour table — is part of the page and works without it.

Hour by hour

Computed on a date when GMT is genuinely in force — using today would be wrong for half the year, because a standard-time abbreviation does not exist in summer.

GMT	UTC
00:00	00:00
01:00	01:00
02:00	02:00
03:00	03:00
04:00	04:00
05:00	05:00
06:00	06:00
07:00	07:00
08:00	08:00
09:00	09:00
10:00	10:00
11:00	11:00
12:00	12:00
13:00	13:00
14:00	14:00
15:00	15:00
16:00	16:00
17:00	17:00
18:00	18:00
19:00	19:00
20:00	20:00
21:00	21:00
22:00	22:00
23:00	23:00

What these abbreviations actually are

	GMT	UTC
Full name	Greenwich Mean Time	Coordinated Universal Time
Representative zone	Etc/GMT	UTC
Offset	UTC+0	UTC+0
Seasonal	Standard time	Standard time
Zone changes in 2026	0	0
Other meanings	1	None in common use

Common questions

What is the difference between GMT and UTC?: UTC is the same time of GMT. GMT means Greenwich Mean Time at UTC+0, and UTC means Coordinated Universal Time at UTC+0.
Which time zone does this page use for GMT?: Etc/GMT. An abbreviation is not a time zone — it is a label a zone wears for part of the year — so every calculation here uses a named IANA zone and says which one. If you are writing code, use Etc/GMT rather than the string "GMT".
Does GMT mean anything else?: Yes: United Kingdom local time in winter at UTC+0. Britain is on GMT only from late October to late March; the rest of the year it is on BST, an hour ahead.
Is GMT a daylight saving abbreviation?: No. GMT is the standard-time abbreviation. When daylight saving is in force, the same zone uses a different one.