What is AST in GMT?
Greenwich Mean Time is 4 hours ahead
Convert a time
GMT — Greenwich Mean Time
8:00 am
GMT, Sat
- Time in Halifax
- 4:28:43 AM
- Time in Greenwich
- 8:28:43 AM
- Difference
- +4 h
- Next clock change
- March 14, 2027
When the difference changes
Atlantic Time and Greenwich Mean 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 – March 14, 2027Greenwich Mean Time is 4 hours ahead
- March 14, 2027 – November 7, 2027Greenwich Mean Time is 3 hours ahead
- November 7, 2027 – onwardsGreenwich Mean Time is 4 hours ahead
Periods shorter than a day are not listed. Each zone changes at its own local time, so on a date when both move there are a few hours when the gap is briefly something else.
Daylight saving
Atlantic Time
Clocks go forward one hour — 2:00 am becomes 3:00 am local time, and the zone is on ADT after that.
Greenwich Mean Time
Greenwich Mean Time stays on GMT all year, so its offset from UTC never moves.
AST to GMT conversion table
Every hour of Saturday, November 7, 2026, converted from Atlantic Time to Greenwich Mean Time. 4 of the 24 hours fall on a different calendar day in Greenwich, which is marked.
- 12:00 am AST
- 4:00 am GMT
- 1:00 am AST
- 5:00 am GMT
- 2:00 am AST
- 6:00 am GMT
- 3:00 am AST
- 7:00 am GMT
- 4:00 am AST
- 8:00 am GMT
- 5:00 am AST
- 9:00 am GMT
- 6:00 am AST
- 10:00 am GMT
- 7:00 am AST
- 11:00 am GMT
- 8:00 am AST
- 12:00 pm GMT
- 9:00 am AST
- 1:00 pm GMT
- 10:00 am AST
- 2:00 pm GMT
- 11:00 am AST
- 3:00 pm GMT
- 12:00 pm AST
- 4:00 pm GMT
- 1:00 pm AST
- 5:00 pm GMT
- 2:00 pm AST
- 6:00 pm GMT
- 3:00 pm AST
- 7:00 pm GMT
- 4:00 pm AST
- 8:00 pm GMT
- 5:00 pm AST
- 9:00 pm GMT
- 6:00 pm AST
- 10:00 pm GMT
- 7:00 pm AST
- 11:00 pm GMT
- 8:00 pm AST
- 12:00 am GMT+1 day
- 9:00 pm AST
- 1:00 am GMT+1 day
- 10:00 pm AST
- 2:00 am GMT+1 day
- 11:00 pm AST
- 3:00 am GMT+1 day
Scheduling between the two
Working hours overlap from 9:00 am to 2:00 pm AST, which is 1:00 pm to 6:00 pm GMT. 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 (AST) is used in Nova Scotia, New Brunswick and Puerto Rico
Greenwich Mean Time (GMT) is used in as a fixed UTC+0 offset. Note that the UK itself leaves GMT every summer — see British Time below.
Other conversions
- GMT to AST
- AST to UTC
- AST to EST
- AST to CST
- AST to MST
- AST to PST
- AST to AKST
- AST to HST
- AST to BST
- AST to CET
- AST to IST
- AST to CST (China)
- AST to JST
- AST to AEST
- AST to Mexico City
- AST to BRT
- AST to ART
- AST to EET
- AST to WET
- AST to MSK
- AST to TRT
- AST to SAST
- AST to WAT
- AST to EAT
- AST to GST
- AST to PKT
- AST to ICT
- AST to WIB
- AST to SGT
- AST to HKT
- AST to KST
- AST to PHT
- AST to AWST
- AST to ACST
- AST to NZST
- All zones