AST to GMT Converter
GMT is 4 hours ahead of AST
AST to GMT Conversion Table
Green rows indicate standard business hours (9 AM – 5 PM) in GMT
| AST | GMT |
|---|---|
| 12:00 AM | 4:00 AM |
| 1:00 AM | 5:00 AM |
| 2:00 AM | 6:00 AM |
| 3:00 AM | 7:00 AM |
| 4:00 AM | 8:00 AM |
| 5:00 AM | 9:00 AM |
| 6:00 AM | 10:00 AM |
| 7:00 AM | 11:00 AM |
| 8:00 AM | 12:00 PM |
| 9:00 AM | 1:00 PM |
| 10:00 AM | 2:00 PM |
| 11:00 AM | 3:00 PM |
| 12:00 PM | 4:00 PM |
| 1:00 PM | 5:00 PM |
| 2:00 PM | 6:00 PM |
| 3:00 PM | 7:00 PM |
| 4:00 PM | 8:00 PM |
| 5:00 PM | 9:00 PM |
| 6:00 PM | 10:00 PM |
| 7:00 PM | 11:00 PM |
| 8:00 PM | 12:00 AM +1d |
| 9:00 PM | 1:00 AM +1d |
| 10:00 PM | 2:00 AM +1d |
| 11:00 PM | 3:00 AM +1d |
Converting Atlantic Standard Time to Greenwich Mean Time
Atlantic Standard Time (AST) and Greenwich Mean Time (GMT) are separated by a 4 hours time difference. GMT is 4 hours ahead of AST. AST is UTC-4, used in Canada, Puerto Rico, US Virgin Islands, while GMT is UTC+0, used in United Kingdom, Ireland, Portugal.
When converting from AST to GMT, the key reference points to remember are: 9:00 AM AST equals 1:00 PM GMT, 12:00 PM noon AST equals 4:00 PM GMT, and 5:00 PM AST equals 9:00 PM GMT. The conversion table above shows every hour of the day mapped between these two time zones.
Scheduling Across AST and GMT
For professionals scheduling meetings between AST and GMT, 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
AST observes Daylight Saving Time, switching to ADT (UTC-3) during summer months. GMT observes DST, switching to BST (UTC+1). 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.