Greenwich Mean Time to Canada Atlantic Time
Convert times between Greenwich Mean Time (GMT, UTC+0:00) and Canada Atlantic Time (AST, UTC-4:00). Canada Atlantic Time is 4 hours behind Greenwich Mean Time in standard time.
UTC+0:00 / +1:00→UTC-4:00 / -3:00
Live timezone converterUTC Offset Reference
| Timezone | Abbreviation | Standard offset | DST offset | Country |
|---|---|---|---|---|
| Greenwich Mean Time | GMT / BST | UTC+0:00 | UTC+1:00 | United Kingdom |
| Canada Atlantic Time | AST / ADT | UTC-4:00 | UTC-3:00 | Canada |
* DST offset applies during summer months. Exact transition dates vary by year.
Standard Time Conversion (GMT → AST)
| Greenwich Mean Time | Canada Atlantic Time |
|---|---|
| 12:00 AM GMT | 8:00 PM (prev day) AST |
| 6:00 AM GMT | 2:00 AM AST |
| 9:00 AM GMT | 5:00 AM AST |
| 12:00 PM GMT | 8:00 AM AST |
| 3:00 PM GMT | 11:00 AM AST |
| 6:00 PM GMT | 2:00 PM AST |
| 9:00 PM GMT | 5:00 PM AST |
Daylight Saving Time (DST) Notes
- Greenwich Mean Time observes DST. Clocks advance 1 hour to BST (UTC+1:00) roughly from month 3 to 10.
- Canada Atlantic Time observes DST. Clocks advance 1 hour to ADT (UTC-3:00) roughly from month 3 to 11.
Frequently Asked Questions
How do I convert GMT to AST?
Add (-4) hours to the GMT time to get AST. For example, 9:00 AM GMT = 5:00 AM AST.
What is the current UTC offset for Greenwich Mean Time?
Greenwich Mean Time is UTC+0:00 during standard time (GMT) and UTC+1:00 during summer daylight saving time (BST).
Is Canada Atlantic Time ahead or behind Greenwich Mean Time?
Canada Atlantic Time is 4 hours behind Greenwich Mean Time in standard time.
When is a good time to schedule a meeting between GMT and AST?
A good overlap window is around 3:00 PM GMT / 11:00 AM AST, which falls within business hours for both timezones.
Related Timezone Conversions
Greenwich Mean Time → US Eastern TimeGMT / ESTGreenwich Mean Time → US Central TimeGMT / CSTGreenwich Mean Time → US Mountain TimeGMT / MSTGreenwich Mean Time → US Pacific TimeGMT / PSTGreenwich Mean Time → US Alaska TimeGMT / AKSTGreenwich Mean Time → Hawaii TimeGMT / HSTGreenwich Mean Time → Central European TimeGMT / CETGreenwich Mean Time → Eastern European TimeGMT / EET
Need the exact current time?
Use the live ToolsHub timezone converter to see current times, DST status, and schedule across time zones.