ADT to UTC Converter
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Quick answers
Selected conversion
9:00 am09:00 ADT (UTC-3), Oct 18, 2026 = 12:00 pm12:00 UTC (UTC+0), Oct 18, 2026
ADT is 3 hours behind UTC.
ADT and UTC examples
These examples always use ADT (UTC-3) and UTC (UTC+0). They stay the same when you change the date or time above. The selected conversion may differ when daylight saving time applies.
ADT is 3 hours behind UTC.
How the time difference changes
For most of the year, ADT is 3 hours behind UTC. From Nov 1, 2026 to Mar 14, 2027, AST is 4 hours behind UTC.
For most of the year, working hours of 9:00 am to 6:00 pm in ADT correspond to 12:00 pm to 9:00 pm in UTC. At other times of the year, working hours of 9:00 am to 6:00 pm in AST correspond to 1:00 pm to 10:00 pm in UTC.For most of the year, working hours of 09:00 to 18:00 in ADT correspond to 12:00 to 21:00 in UTC. At other times of the year, working hours of 09:00 to 18:00 in AST correspond to 13:00 to 22:00 in UTC.
Compare ADT time with UTC time, including current local time, UTC offsets, time difference, daylight saving changes, working hours, and shareable meeting times.
Time Difference
Atlantic Daylight Time is 3 hours behind Coordinated Universal Time.
9:00 am09:00 in ADT is 12:00 pm12:00 in UTC
ADT to UTC call time
Best time for a conference call or a meeting is between 9am-3pm09:00-15:00 in ADT which corresponds to 12pm-6pm12:00-18:00 in UTC
9:00 am09:00 Atlantic Daylight Time (ADT). Offset UTC -3:00 hours
12:00 pm12:00 Coordinated Universal Time (UTC). Offset UTC 0:00 hours
9:00 am09:00 ADT / 12:00 pm12:00 UTC
Choose an hour to update the converter. Day labels such as “next day” or “+1” are relative to the selected date in the first column. Use Up and Down arrow keys, Home or End to move between hours, then Enter or Space to select.
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Atlantic Daylight Time
Offset: ADT is 3 hours behind Greenwich Mean Time (GMT).
Countries using this time zone: Bermuda, Canada, Greenland
Principal Cities: The largest city in the ADT time zone is Halifax in Canada, with about 471,559 people. Other major cities in this time zone include Sydney, Moncton, Saint John, Fredericton.
French: HAA - Heure Avancée de l'Atlantique
Today all shaded areas are on ADT.
Daylight Saving: Atlantic Daylight Time (ADT) is a daylight saving/summer time zone. During winter, some places set clocks back one hour and observe Atlantic Standard Time (AST).
Start: Atlantic Daylight Time (ADT) started on Sunday, March 8, 2026 at 2:00 am02:00 local time and clocks were set one hour forward to Sunday, March 8, 2026, 3:00 am03:00. Daylight saving starts annually on the second Sunday of March.
End: Atlantic Daylight Time (ADT) ends on Sunday, November 1, 2026 at 2:00 am02:00 local time and clocks are set one hour back to Sunday, November 1, 2026, 1:00 am01:00 local standard time instead. Daylight saving ends annually on the first Sunday of November.
See Canada daylight saving time and upcoming clock changes worldwide.
ADT representations, usage and related time zones
- -03 - basic short
- -0300 - basic
- -03:00 - extended
- -0300 - sign character (-) followed by a four digit time providing hours (03) and minutes (00) of the offset. Indicates an offset of three hours to the west of the zero meridian.
- Papa - Military abbreviation for ADT
- P - short form of 'Papa'
- America/Glace_Bay
- America/Goose_Bay
- America/Halifax
- America/Moncton
- America/Thule
- Atlantic/Bermuda
- Canada/Atlantic
- ADT - Atlantic Daylight Time
- PMT - Pierre & Miquelon Standard Time
- PMST - Pierre & Miquelon Standard Time
- AMST - Amazon Summer Time
- ART - Argentina Time
- BRT - Brasilia Time
- CLST - Chile Summer Time
- FKST - Falkland Islands Summer Time
- FKT - Falkland Islands Time
- GFT - French Guiana Time
- P - Papa Time Zone
- PYST - Paraguay Summer Time
- PYT - Paraguay Time
- SRT - Suriname Time
- UYT - Uruguay Time
Coordinated Universal Time
Offset: UTC is the same as Greenwich Mean Time (GMT).
Countries using this time zone: Antarctica, Burkina Faso, Faroe Islands, Gambia, Ghana, Greenland, Guernsey, Guinea, Guinea-Bissau, Iceland, Ireland, Isle of Man, Ivory Coast, Jersey, Liberia, Mali, Mauritania, Morocco, Portugal, Saint Helena, São Tomé and Príncipe, Senegal, Sierra Leone, Spain, Togo, United Kingdom, Western Sahara
Principal Cities: The largest city in the UTC time zone is London in the United Kingdom, with about 8.962 million people. Other major cities in this time zone include Abidjan, Bamako, Casablanca, Dakar.
Coordinated Universal Time (UTC) is the world time standard that regulates clocks and time. It is the successor to Greenwich Mean Time (GMT). For casual use, UTC is the same as GMT, but UTC is the standard the scientific community uses.
UTC has been the time standard commonly used across the world since 1972. It is used in many technical fields, such as aviation and meteorology, and to synchronize time across internet networks.
Today some of the lighter areas are on UTC+1 (British Summer Time, Irish Standard Time, WEST).
UTC representations, usage and related time zones
- Z - is the zone designator for the zero UTC/GMT offset, also known as 'Zulu' time
- +00 - basic short
- +0000 - basic
- +00:00 - extended
- +0000 - sign character (+) followed by a four digit time providing hours (00) and minutes (00) of the offset. Indicates the zero UTC/GMT offset.
- Zulu - Military abbreviation for UTC
- Z - short form of 'Zulu'
- Etc/UCT
- Etc/UTC
- Etc/Universal
- Etc/Zulu
- UCT
- UTC
- Universal
- Zulu
- EGST - Eastern Greenland Summer Time
- GMT - Greenwich Mean Time
- WET - Western European Time
- AZOST - Azores Summer Time
- UTC - Coordinated Universal Time
- WT - Western Sahara Standard Time
- Z - Zulu Time Zone