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CST to GMT Time

Easily convert Central Standard Time (CST) to Greenwich Mean Time (GMT) for smooth and precise planning of international business, educational, or personal events between the U.S. and Europe.

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  • Runs in your browser
In short

GMT (UTC+0) is 6 hours ahead of CST (UTC−6) in standard time. 12:20 PM CST is 6:20 PM GMT. During daylight saving time (roughly March to early November) the gap is 5 hours, so 12:20 PM CDT is 5:20 PM GMT.

About CST to GMT Time

CST covers Chicago, Dallas, Houston, Mexico City and Winnipeg. GMT covers Reykjavik and Accra, and the reference for every other zone.

Working days overlap between 09:00 and 13:00 CST, which is 14:00–18:00 in GMT. That window is where calls land without anyone working late.

The clocks do not change on the same day, so a recurring meeting can shift by an hour in March and again in November. Check any standing call in the two weeks after each change.

How it works

GMT / UTC is 6 hours ahead of Central Time (Chicago) between November and March, and 5 hours ahead the rest of the year.

  1. Take the CST time you want to convert.
  2. Add 6 hours between autumn and spring, or 5 hours during daylight saving.
  3. Roll the date forward or back if the result crosses midnight.

The gap changes because the two places start and end daylight saving on different dates — for a few weeks each spring and autumn the difference is an hour off its usual value. The converter above uses the live IANA time zone database, so it is right on those days too.

Zone details: CST is −6 in winter and −5 in summer (UTC), GMT is +0 all year.

Examples

A working day in CST, seen from GMT (during daylight saving):

CST to GMT at a glance
CSTGMT
09:00 CST14:00 GMT
12:00 CST17:00 GMT
15:00 CST20:00 GMT
18:00 CST23:00 GMT
21:00 CST02:00 GMT (next day)

Meetings usually work best where the two working days overlap. Drag the timeline above to see the overlap for any hour, or use the full time zone converter for any other pair of cities.

CST to GMT Time: frequently asked questions

What is the time difference between CST and GMT?
GMT is 6 hours ahead of CST in standard time (CST is UTC−6, GMT is UTC+0). The gap can change by an hour for part of the year because CST observes daylight saving (CDT) and GMT does not observe daylight saving.
What is 9 AM CST in GMT?
9:00 AM CST is 3:00 PM GMT (standard time).
Where is CST used?
Central Standard Time (UTC−6) is used in the US Central (Chicago, Dallas).
Where is GMT used?
Greenwich Mean Time (always UTC+0; the UK switches to BST in summer) (UTC+0) is used in the UK in winter, Iceland and parts of West Africa.