MDT to AST converter
AST is 3 hours ahead of MDT today. MDT (Mountain Daylight Time) - currently UTC−7; AST (Atlantic Standard Time) - currently UTC−4.
6 hours of the workday overlap: 9 AM-3 PM MDT is 12 PM-6 PM AST. Quick answers: 9 AM MDT = 12 PM AST, 12 PM MDT = 3 PM AST, 5 PM MDT = 8 PM AST.
Convert a time
AST
--:--
Working hours side by side
columns: MDT hours PING · 09–18 local MAYBE · 07–09, 18–21 NOT NOW · 21–07Outlined: everyone can be pinged
MDT to AST conversion table
| MDT | AST | Verdict in AST |
|---|---|---|
| 12 AM · 00:00 | 3 AM · 03:00 | NOT NOW |
| 1 AM · 01:00 | 4 AM · 04:00 | NOT NOW |
| 2 AM · 02:00 | 5 AM · 05:00 | NOT NOW |
| 3 AM · 03:00 | 6 AM · 06:00 | NOT NOW |
| 4 AM · 04:00 | 7 AM · 07:00 | MAYBE |
| 5 AM · 05:00 | 8 AM · 08:00 | MAYBE |
| 6 AM · 06:00 | 9 AM · 09:00 | PING |
| 7 AM · 07:00 | 10 AM · 10:00 | PING |
| 8 AM · 08:00 | 11 AM · 11:00 | PING |
| 9 AM · 09:00 | 12 PM · 12:00 | PING |
| 10 AM · 10:00 | 1 PM · 13:00 | PING |
| 11 AM · 11:00 | 2 PM · 14:00 | PING |
| 12 PM · 12:00 | 3 PM · 15:00 | PING |
| 1 PM · 13:00 | 4 PM · 16:00 | PING |
| 2 PM · 14:00 | 5 PM · 17:00 | PING |
| 3 PM · 15:00 | 6 PM · 18:00 | MAYBE |
| 4 PM · 16:00 | 7 PM · 19:00 | MAYBE |
| 5 PM · 17:00 | 8 PM · 20:00 | MAYBE |
| 6 PM · 18:00 | 9 PM · 21:00 | NOT NOW |
| 7 PM · 19:00 | 10 PM · 22:00 | NOT NOW |
| 8 PM · 20:00 | 11 PM · 23:00 | NOT NOW |
| 9 PM · 21:00 | 12 AM · 00:00 (next day) | NOT NOW |
| 10 PM · 22:00 | 1 AM · 01:00 (next day) | NOT NOW |
| 11 PM · 23:00 | 2 AM · 02:00 (next day) | NOT NOW |
Cities on MDT
America/DenverCities on AST
America/HalifaxOther conversions
All convertersQuestions
What is the time difference between MDT and AST?
AST (Atlantic Standard Time) is 3 hours ahead of MDT (Mountain Daylight Time) right now: UTC−7 versus UTC−4.
What is 9 AM MDT in AST?
9:00 AM MDT is 12 PM AST.
What is 5 PM MDT in AST?
5:00 PM MDT is 8 PM AST.
Does daylight saving change the MDT–AST difference?
Denver switches between MDT and MST; next change Sunday, 14 March 2027 (UTC−7 → UTC−6). Halifax switches between AST; next change Sunday, 14 March 2027 (UTC−4 → UTC−3).