GMT to AST Converter
AST is 4 hours behind GMT
GMT to AST Conversion Table
Green rows indicate standard business hours (9 AM – 5 PM) in AST
| GMT | AST |
|---|---|
| 12:00 AM | 8:00 PM -1d |
| 1:00 AM | 9:00 PM -1d |
| 2:00 AM | 10:00 PM -1d |
| 3:00 AM | 11:00 PM -1d |
| 4:00 AM | 12:00 AM |
| 5:00 AM | 1:00 AM |
| 6:00 AM | 2:00 AM |
| 7:00 AM | 3:00 AM |
| 8:00 AM | 4:00 AM |
| 9:00 AM | 5:00 AM |
| 10:00 AM | 6:00 AM |
| 11:00 AM | 7:00 AM |
| 12:00 PM | 8:00 AM |
| 1:00 PM | 9:00 AM |
| 2:00 PM | 10:00 AM |
| 3:00 PM | 11:00 AM |
| 4:00 PM | 12:00 PM |
| 5:00 PM | 1:00 PM |
| 6:00 PM | 2:00 PM |
| 7:00 PM | 3:00 PM |
| 8:00 PM | 4:00 PM |
| 9:00 PM | 5:00 PM |
| 10:00 PM | 6:00 PM |
| 11:00 PM | 7:00 PM |
Converting Greenwich Mean Time to Atlantic Standard Time
Greenwich Mean Time (GMT) and Atlantic Standard Time (AST) are separated by a 4 hours time difference. AST is 4 hours behind GMT. GMT is UTC+0, used in United Kingdom, Ireland, Portugal, while AST is UTC-4, used in Canada, Puerto Rico, US Virgin Islands.
When converting from GMT to AST, the key reference points to remember are: 9:00 AM GMT equals 5:00 AM AST, 12:00 PM noon GMT equals 8:00 AM AST, and 5:00 PM GMT equals 1:00 PM AST. The conversion table above shows every hour of the day mapped between these two time zones.
Scheduling Across GMT and AST
For professionals scheduling meetings between GMT and AST, finding overlapping business hours is essential. Standard business hours are typically 9:00 AM to 5:00 PM in each time zone. Given the 4 hours difference, the window of overlap may be limited. Use the highlighted working hours in the conversion table above to quickly identify suitable meeting times.
Daylight Saving Time Considerations
GMT observes Daylight Saving Time, switching to BST (UTC+1) during summer months. AST observes DST, switching to ADT (UTC-3). During DST transitions, the time difference between these zones may temporarily change by 1 hour. Always verify the current offset during spring and fall transition periods.