ADT to GMT Converter
From Atlantic Daylight Time to Greenwich Mean Time: gMT is 3 hours ahead of ADT. Use the editable converter to translate any ADT time — including the date — into GMT.
Daylight saving notes
In the United States and Canada, daylight saving time runs from the second Sunday in March to the first Sunday in November. That affects Atlantic Daylight Time (ADT).
ADT to GMT conversion chart
For example, a 9:00 AM ADT meeting takes place at 12:00 PM GMT. Concretely, when Halifax (ADT) and London (winter) (GMT) set up a call, gMT is 3 hours ahead of ADT.
| ADT time | GMT time |
|---|---|
| 12:00 AM | 3:00 AM |
| 1:00 AM | 4:00 AM |
| 2:00 AM | 5:00 AM |
| 3:00 AM | 6:00 AM |
| 4:00 AM | 7:00 AM |
| 5:00 AM | 8:00 AM |
| 6:00 AM | 9:00 AM |
| 7:00 AM | 10:00 AM |
| 8:00 AM | 11:00 AM |
| 9:00 AM | 12:00 PM |
| 10:00 AM | 1:00 PM |
| 11:00 AM | 2:00 PM |
| 12:00 PM | 3:00 PM |
| 1:00 PM | 4:00 PM |
| 2:00 PM | 5:00 PM |
| 3:00 PM | 6:00 PM |
| 4:00 PM | 7:00 PM |
| 5:00 PM | 8:00 PM |
| 6:00 PM | 9:00 PM |
| 7:00 PM | 10:00 PM |
| 8:00 PM | 11:00 PM |
| 9:00 PM | 12:00 AM+1 day |
| 10:00 PM | 1:00 AM+1 day |
| 11:00 PM | 2:00 AM+1 day |
This chart uses the fixed ADT and GMT offsets; the live converter above follows current daylight saving.
Convert ADT to GMT Time Zone
Below are the answers people search for most when converting Atlantic Daylight Time (ADT) to Greenwich Mean Time (GMT).
How do I convert ADT to GMT?
It takes three quick steps:
- Click the ADT field on the left and pick the time you want to convert.
- The matching GMT time updates on the right automatically — there’s no button to press.
- Need a different day? Click the date field and the result follows, rolling over if it crosses midnight.
What is the time difference between ADT and GMT?
GMT is 3 hours ahead of ADT. In everyday terms, once you know the time on one side you just add 3 hours to get the other — so a call between Halifax and London (winter) is always 3 hours apart.
What time is it in GMT right now?
Right now the time in Greenwich Mean Time (GMT) is Monday, June 29, 2026 · 5:53:57 PM. It ticks every second, so you’re always looking at the live GMT clock.
What time is it in ADT right now?
And in Atlantic Daylight Time (ADT), it’s currently Monday, June 29, 2026 · 2:53:57 PM. Compare the two and the 3 hours gap is easy to see.
Planning a meeting across ADT and GMT?
For example, a 9:00 AM ADT meeting takes place at 12:00 PM GMT. The trick is to aim for a slot that lands inside normal working hours on both sides. Once you’ve found a time, hit Share on the converter to copy a link with the time built in — easy to send to a colleague. Juggling three or more zones? The meeting planner highlights the hours that overlap for everyone.
How does daylight saving affect ADT to GMT?
The labels ADT and GMT are fixed offsets, so the result on this page is always exact. One side switches between standard and summer time while the other stays put, so the real-world gap can shift by an hour for part of the year. It's worth checking which label a region is actually using before you lock in a time.
Why can you trust this ADT to GMT converter?
Every conversion here is calculated from the IANA time zone database — the same source your phone, computer, and browser rely on. Plenty of tools hard-code a single offset, which quietly goes wrong whenever a region changes its rules or flips for daylight saving. We follow the real rules instead, so ADT to GMT stays accurate for today and for any past or future date you type in.
Convert ADT to other time zones
- UTC Coordinated Universal Time
- GMT Greenwich Mean Time
- EST Eastern Standard Time
- EDT Eastern Daylight Time
- CST Central Standard Time
- CDT Central Daylight Time
- MST Mountain Standard Time
- MDT Mountain Daylight Time
- PST Pacific Standard Time
- PDT Pacific Daylight Time
- AKST Alaska Standard Time
- AKDT Alaska Daylight Time
- HST Hawaii Standard Time
- AST Atlantic Standard Time
- NST Newfoundland Standard Time
- NDT Newfoundland Daylight Time
- BRT Brasília Time
- ART Argentina Time
- WET Western European Time
- WEST Western European Summer Time
- CET Central European Time
- CEST Central European Summer Time
- EET Eastern European Time
- EEST Eastern European Summer Time
- BST British Summer Time
- IST Irish Standard Time
- MSK Moscow Standard Time
- TRT Turkey Time
- WAT West Africa Time
- CAT Central Africa Time
- EAT East Africa Time
- SAST South Africa Standard Time
- GST Gulf Standard Time
- IST Israel Standard Time
- IDT Israel Daylight Time
- IST India Standard Time
- PKT Pakistan Standard Time
- BDT Bangladesh Standard Time
- ICT Indochina Time
- WIB Western Indonesian Time
- WITA Central Indonesian Time
- WIT Eastern Indonesian Time
- CST China Standard Time
- HKT Hong Kong Time
- SGT Singapore Time
- PHT Philippine Time
- JST Japan Standard Time
- KST Korea Standard Time
- AWST Australian Western Standard Time
- ACST Australian Central Standard Time
- ACDT Australian Central Daylight Time
- AEST Australian Eastern Standard Time
- AEDT Australian Eastern Daylight Time
- NZST New Zealand Standard Time
- NZDT New Zealand Daylight Time
Convert to GMT from other time zones
- UTC Coordinated Universal Time
- EST Eastern Standard Time
- EDT Eastern Daylight Time
- CST Central Standard Time
- CDT Central Daylight Time
- MST Mountain Standard Time
- MDT Mountain Daylight Time
- PST Pacific Standard Time
- PDT Pacific Daylight Time
- AKST Alaska Standard Time
- AKDT Alaska Daylight Time
- HST Hawaii Standard Time
- AST Atlantic Standard Time
- ADT Atlantic Daylight Time
- NST Newfoundland Standard Time
- NDT Newfoundland Daylight Time
- BRT Brasília Time
- ART Argentina Time
- WET Western European Time
- WEST Western European Summer Time
- CET Central European Time
- CEST Central European Summer Time
- EET Eastern European Time
- EEST Eastern European Summer Time
- BST British Summer Time
- IST Irish Standard Time
- MSK Moscow Standard Time
- TRT Turkey Time
- WAT West Africa Time
- CAT Central Africa Time
- EAT East Africa Time
- SAST South Africa Standard Time
- GST Gulf Standard Time
- IST Israel Standard Time
- IDT Israel Daylight Time
- IST India Standard Time
- PKT Pakistan Standard Time
- BDT Bangladesh Standard Time
- ICT Indochina Time
- WIB Western Indonesian Time
- WITA Central Indonesian Time
- WIT Eastern Indonesian Time
- CST China Standard Time
- HKT Hong Kong Time
- SGT Singapore Time
- PHT Philippine Time
- JST Japan Standard Time
- KST Korea Standard Time
- AWST Australian Western Standard Time
- ACST Australian Central Standard Time
- ACDT Australian Central Daylight Time
- AEST Australian Eastern Standard Time
- AEDT Australian Eastern Daylight Time
- NZST New Zealand Standard Time
- NZDT New Zealand Daylight Time
Frequently asked questions
How many hours ahead of ADT is GMT?
GMT is 3 hours ahead of ADT — a fixed 3 hours difference, since both are fixed-offset labels.
What time is it in GMT when it's 12:00 PM ADT?
When it's 12:00 PM (noon) ADT, it's 3:00 PM GMT.
Do ADT or GMT use daylight saving time?
Atlantic Daylight Time (ADT) observes daylight saving, alternating with AST; Greenwich Mean Time (GMT) is a fixed offset with no daylight saving.
Why might the real-world ADT–GMT difference change during the year?
The labels ADT and GMT are fixed offsets, so this converter is always exact. But Atlantic Daylight Time's region switches between standard and summer time, so for part of the year you may actually want AST to GMT. Always check which label a region is currently using before you schedule.