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