GMT to CST Time Converter
CST is 6 hours behind GMT. The UK and Ireland are currently on BST (UTC+1:00), and The US Central states are currently on CDT (UTC-5:00).
Best Time to Call Between GMT and CST
Both zones are inside normal business hours between 3:00 PM and 5:00 PM GMT — that's 9:00 AM to 11:00 AM CST. That's a 2-hour window.
both at work GMT only CST only neither — hours along the strip are GMT.
Common Times Converted
GMT on the left, CST on the right.
GMT to CST: Full 24-Hour Conversion Table
Shaded rows are working hours; the darker shade marks the hours when both zones are at work.
| GMT | CST | Working hours |
|---|---|---|
| 12:00 AM | 6:00 PM prev day | — |
| 1:00 AM | 7:00 PM prev day | — |
| 2:00 AM | 8:00 PM prev day | — |
| 3:00 AM | 9:00 PM prev day | — |
| 4:00 AM | 10:00 PM prev day | — |
| 5:00 AM | 11:00 PM prev day | — |
| 6:00 AM | 12:00 AM | — |
| 7:00 AM | 1:00 AM | — |
| 8:00 AM | 2:00 AM | — |
| 9:00 AM | 3:00 AM | GMT only |
| 10:00 AM | 4:00 AM | GMT only |
| 11:00 AM | 5:00 AM | GMT only |
| 12:00 PM | 6:00 AM | GMT only |
| 1:00 PM | 7:00 AM | GMT only |
| 2:00 PM | 8:00 AM | GMT only |
| 3:00 PM | 9:00 AM | Both zones |
| 4:00 PM | 10:00 AM | Both zones |
| 5:00 PM | 11:00 AM | CST only |
| 6:00 PM | 12:00 PM | CST only |
| 7:00 PM | 1:00 PM | CST only |
| 8:00 PM | 2:00 PM | CST only |
| 9:00 PM | 3:00 PM | CST only |
| 10:00 PM | 4:00 PM | CST only |
| 11:00 PM | 5:00 PM | — |
What GMT and CST Actually Are
GMT — Greenwich Mean Time
The UK and Ireland in winter, plus Iceland, Portugal and much of West Africa. Standing at UTC as written, and the region does change its clocks, so its live offset moves by an hour twice a year. The next change is on Sunday, October 25, 2026, to GMT. Often used loosely as a synonym for UTC. They differ by less than a second, so for scheduling they are interchangeable.
Britain ran an experiment from 1968 to 1971 on permanent UTC+1, abandoning GMT entirely. It was scrapped after complaints about dark winter mornings in Scotland.
CST — Central Standard Time
Chicago, Houston, Dallas, Mexico City, Winnipeg. Standing at UTC-6:00 as written, and the region does change its clocks, so its live offset moves by an hour twice a year. The next change is on Sunday, November 1, 2026, to CST. CST also stands for China Standard Time (UTC+8) and Cuba Standard Time (UTC-5). This page covers the North American one.
Saskatchewan sits inside the Central zone but never changes its clocks, so it matches CST in winter and its neighbors' MDT in summer.
What This Means in Practice
Both sides change clocks, on different dates
Both regions observe daylight saving but do not switch on the same day, so for a week or two each spring and fall the gap between them is an hour different from the rest of the year. Those short windows are where recurring invitations quietly break.
Major Cities in Each Zone
Cities on GMT
Cities on CST
Frequently Asked Questions
What is the time difference between GMT and CST?
CST is 6 hours behind GMT.
What is 9:00 AM GMT in CST?
9:00 AM GMT is 3:00 AM CST.
What are the best hours to schedule a call between GMT and CST?
Between 3:00 PM and 5:00 PM GMT, which is 9:00 AM to 11:00 AM CST. Both sides are inside normal business hours through that window.
Does the difference between GMT and CST change during the year?
Yes. Both regions observe daylight saving, and they do not switch on the same dates, so the gap shifts by an hour at least twice a year. The next clock change is on Sunday, October 25, 2026.
Does GMT always mean Greenwich Mean Time?
Often used loosely as a synonym for UTC. They differ by less than a second, so for scheduling they are interchangeable.
Does CST always mean Central Standard Time?
CST also stands for China Standard Time (UTC+8) and Cuba Standard Time (UTC-5). This page covers the North American one.