The short answer
4am in Atlantic Standard Time is 1am in Mountain Time.
Atlantic Standard Time is 3 hours ahead of Mountain Time. It lands deep outside working hours in Mountain Time — see the best time to meet below for a friendlier slot.
Atlantic Standard Time☾
4am
Mountain Time☾
1am
Right now
6:53amADT · UTC-03:00 · Mon, Jun 22
3:53amMDT · UTC-06:00 · Mon, Jun 22
Read across to convert
Atlantic Standard Time
ADT · UTC-03:00
Mountain Time
MDT · UTC-06:00
Pinned4amAtlantic Standard Time=1amMountain Time
12amMon
9pmSun ·−1d
1am
10pmSun ·−1d
2am
11pmSun ·−1d
3am
12amMon
PINNED
4am
1am
5am
2am
NOW
6am
3am
7am
4am
8am
5am
9am
WORK6am
10am
WORK7am
11am
WORK8am
12pm
WORK9am
WORK1pm
WORK10am
WORK2pm
WORK11am
WORK3pm
WORK12pm
WORK4pm
WORK1pm
WORK5pm
2pm
WORK6pm
3pm
WORK7pm
4pm
WORK8pm
5pm
9pm
6pm
10pm
7pm
11pm
8pm
daylightnightworking hoursoverlap
Best time to meet=
Best for a call
Atlantic Standard Time
12pm–5pm
Mountain Time
9am–2pm
Popular conversions
Quick reference.
9amAtlantic Standard Time=6amMountain Time
12pmAtlantic Standard Time=9amMountain Time
3pmAtlantic Standard Time=12pmMountain Time
5pmAtlantic Standard Time=2pmMountain Time
9pmAtlantic Standard Time=6pmMountain Time
In context
What each side covers.
Atlantic Standard Time
6:53amADT · UTC-03:00
Canada & Caribbean
Mountain Time
3:53amMDT · UTC-06:00
Cities on this clock
Related converters
Other popular pairs.
Pacific Time
2:53am
India Standard Time
3:23pm
Pacific Time to India12 hours 30 minutes behind
Eastern Standard Time
5:53am
Central European Time
11:53am
Eastern Time to Central Europe6 hours behind
India Standard Time
3:23pm
Eastern Standard Time
5:53am
India to Eastern Time9 hours 30 minutes ahead
Greenwich Mean Time
10:53am
India Standard Time
3:23pm
London to India4 hours 30 minutes behind
Pacific Standard Time
2:53am
Eastern Standard Time
5:53am
Pacific to Eastern Time3 hours behind
Central European Time
11:53am
India Standard Time
3:23pm
Central Europe to India3 hours 30 minutes behind
Frequently asked
Quick answers about converting between Atlantic Standard Time and Mountain Time. Can't find what you need? Email [email protected].
- What is the time difference between Atlantic Standard Time and Mountain Time?
- Atlantic Standard Time is 3 hours ahead of Mountain Time right now. We always show the live, daylight-saving-correct difference, so this figure already accounts for whichever side is observing summer time today.
- When it's 4am in Atlantic Standard Time, what time is it in Mountain Time?
- 4am in Atlantic Standard Time is 1am in Mountain Time. It lands deep outside working hours in Mountain Time — see the best time to meet below for a friendlier slot. Use the hour-by-hour table above to read any other time across.
- What's the best time for a call between Atlantic Standard Time and Mountain Time?
- 12pm–5pm in Atlantic Standard Time lines up with 9am–2pm in Mountain Time — both sides are inside a 9-to-5 working day.
- Does this account for daylight saving time?
- Yes. We track every clock change in both places, so the abbreviations you see — ADT and MDT — are the ones actually in effect right now, not a fixed all-year value. When either side changes its clocks, this page updates automatically.
- Why is the date sometimes different on each side?
- When two places are far enough apart, the same moment can fall on different calendar days. That is why some conversions are marked "previous day" or "next day" — it is the same instant in time, read off two clocks that crossed midnight at different points.