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MST to AST
Convert MST (Mountain Standard Time, UTC−07:00) to AST (Atlantic Standard Time, UTC−04:00). AST is 3 hours ahead of MST.
MST
—
Mountain Standard Time
→
AST
—
Atlantic Standard Time
Convert a specific time
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MST to AST conversion chart (24-hour)
| MST | AST |
|---|---|
| 00:00 | 03:00 |
| 01:00 | 04:00 |
| 02:00 | 05:00 |
| 03:00 | 06:00 |
| 04:00 | 07:00 |
| 05:00 | 08:00 |
| 06:00 | 09:00 |
| 07:00 | 10:00 |
| 08:00 | 11:00 |
| 09:00 | 12:00 |
| 10:00 | 13:00 |
| 11:00 | 14:00 |
| 12:00 | 15:00 |
| 13:00 | 16:00 |
| 14:00 | 17:00 |
| 15:00 | 18:00 |
| 16:00 | 19:00 |
| 17:00 | 20:00 |
| 18:00 | 21:00 |
| 19:00 | 22:00 |
| 20:00 | 23:00 |
| 21:00 | 00:00 +1d |
| 22:00 | 01:00 +1d |
| 23:00 | 02:00 +1d |
MST to AST time conversion
The difference between MST and AST is fixed: AST is 3 hours ahead of MST. For example, 9:00 AM (09:00) MST is 12:00 AST, and 6:00 PM (18:00) MST is 21:00 AST. The chart above lists the conversion for every hour of the day.
These conversions use each zone's standard UTC offset — UTC−07:00 for MST (Mountain Standard Time) and UTC−04:00 for AST (Atlantic Standard Time) — so the result is exact and does not shift with Daylight Saving Time. To convert a real calendar date between cities with automatic DST handling, use the full time zone converter.