What is AST in UTC?
Coordinated Universal Time is 3 hours ahead
Atlantic Time is on UTC−3:00 and Coordinated Universal Time is on UTC+0:00 right now. Atlantic Time is on daylight saving, so its clocks read ADT. The gap changes during the year — see below.
- Time in Halifax
- 11:56 pm
- Time in the prime meridian
- 2:56 am
- Difference
- +3 h
- Next clock change
- November 1, 2026
Convert a time
UTC — Coordinated Universal Time
2:00 am
Wed, the next day
When the difference changes
Atlantic Time and Coordinated Universal Time do not change their clocks on the same dates, so the gap between them is not the same all year. Most converters show only today’s figure. These are the periods ahead:
- Now – November 1, 2026Coordinated Universal Time is 3 hours ahead
- November 1, 2026 – March 14, 2027Coordinated Universal Time is 4 hours ahead
- March 14, 2027 – onwardsCoordinated Universal Time is 3 hours ahead
Periods shorter than a day are not listed: both zones change at 2am in their own local time, so there are a few hours on each transition date when the gap is briefly something else.
Daylight saving
Atlantic Time
Clocks go back one hour at 2am local time, becoming AST.
Coordinated Universal Time
Coordinated Universal Time stays on UTC all year, so its offset from UTC never moves.
AST to UTC conversion table
Every hour of Tuesday, September 22, 2026, converted from Atlantic Time to Coordinated Universal Time. 3 of the 24 hours fall on a different calendar day in the prime meridian, which is marked.
- 12:00 am ADT
- 3:00 am UTC
- 1:00 am ADT
- 4:00 am UTC
- 2:00 am ADT
- 5:00 am UTC
- 3:00 am ADT
- 6:00 am UTC
- 4:00 am ADT
- 7:00 am UTC
- 5:00 am ADT
- 8:00 am UTC
- 6:00 am ADT
- 9:00 am UTC
- 7:00 am ADT
- 10:00 am UTC
- 8:00 am ADT
- 11:00 am UTC
- 9:00 am ADT
- 12:00 pm UTC
- 10:00 am ADT
- 1:00 pm UTC
- 11:00 am ADT
- 2:00 pm UTC
- 12:00 pm ADT
- 3:00 pm UTC
- 1:00 pm ADT
- 4:00 pm UTC
- 2:00 pm ADT
- 5:00 pm UTC
- 3:00 pm ADT
- 6:00 pm UTC
- 4:00 pm ADT
- 7:00 pm UTC
- 5:00 pm ADT
- 8:00 pm UTC
- 6:00 pm ADT
- 9:00 pm UTC
- 7:00 pm ADT
- 10:00 pm UTC
- 8:00 pm ADT
- 11:00 pm UTC
- 9:00 pm ADT
- 12:00 am UTC+1 day
- 10:00 pm ADT
- 1:00 am UTC+1 day
- 11:00 pm ADT
- 2:00 am UTC+1 day
Scheduling between the two
Working hours overlap from 9:00 am to 3:00 pm ADT, which is 12:00 pm to 6:00 pm UTC. Anything inside that window falls in the normal working day at both ends.
A note on AST: it can also mean Arabia Standard Time (UTC+3). This page means Atlantic Time.
Atlantic Time (ADT) is used in Nova Scotia, New Brunswick and Puerto Rico
Coordinated Universal Time (UTC) is used in aviation, computing, and science worldwide. UTC never changes for daylight saving.