AST to GMT Converter
Need to convert Atlantic Standard Time to Greenwich Mean Time? GMT is 4 hours ahead of AST. Edit the time or date below and the GMT result updates live.
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 Standard Time (AST).
AST to GMT conversion chart
For example, a 9:00 AM AST meeting takes place at 1:00 PM GMT. Concretely, when Halifax (AST) and London (winter) (GMT) set up a call, gMT is 4 hours ahead of AST.
| AST time | GMT time |
|---|---|
| 12:00 AM | 4:00 AM |
| 1:00 AM | 5:00 AM |
| 2:00 AM | 6:00 AM |
| 3:00 AM | 7:00 AM |
| 4:00 AM | 8:00 AM |
| 5:00 AM | 9:00 AM |
| 6:00 AM | 10:00 AM |
| 7:00 AM | 11:00 AM |
| 8:00 AM | 12:00 PM |
| 9:00 AM | 1:00 PM |
| 10:00 AM | 2:00 PM |
| 11:00 AM | 3:00 PM |
| 12:00 PM | 4:00 PM |
| 1:00 PM | 5:00 PM |
| 2:00 PM | 6:00 PM |
| 3:00 PM | 7:00 PM |
| 4:00 PM | 8:00 PM |
| 5:00 PM | 9:00 PM |
| 6:00 PM | 10:00 PM |
| 7:00 PM | 11:00 PM |
| 8:00 PM | 12:00 AM+1 day |
| 9:00 PM | 1:00 AM+1 day |
| 10:00 PM | 2:00 AM+1 day |
| 11:00 PM | 3:00 AM+1 day |
This chart uses the fixed AST and GMT offsets; the live converter above follows current daylight saving.
Convert AST to GMT Time Zone
A quick guide to AST → GMT: the time gap, the live clocks, scheduling tips, and how we keep it accurate.
How do I convert AST to GMT?
It takes three quick steps:
- Click the AST 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 AST and GMT?
GMT is 4 hours ahead of AST. In everyday terms, once you know the time on one side you just add 4 hours to get the other — so a call between Halifax and London (winter) is always 4 hours apart.
What's the current time in GMT?
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.
And what time is it in AST?
And in Atlantic Standard Time (AST), it’s currently Monday, June 29, 2026 · 1:53:57 PM. Compare the two and the 4 hours gap is easy to see.
Planning a meeting across AST and GMT?
For example, a 9:00 AM AST meeting takes place at 1:00 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.
Does daylight saving time change the AST–GMT difference?
The labels AST 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.
How accurate is this AST to GMT conversion?
We don’t guess. AST and GMT times are worked out from the official IANA time zone database, the trusted standard that operating systems use worldwide. Because daylight-saving rules and regional offsets do change over time, we track those updates rather than relying on a fixed number — which is exactly where many converters slip up.
Convert AST 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
- 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
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 AST is GMT?
GMT is 4 hours ahead of AST — a fixed 4 hours difference, since both are fixed-offset labels.
What time is it in GMT when it's 12:00 PM AST?
When it's 12:00 PM (noon) AST, it's 4:00 PM GMT.
Do AST or GMT use daylight saving time?
Atlantic Standard Time (AST) observes daylight saving, alternating with ADT; Greenwich Mean Time (GMT) is a fixed offset with no daylight saving.
Why might the real-world AST–GMT difference change during the year?
The labels AST and GMT are fixed offsets, so this converter is always exact. But Atlantic Standard Time's region switches between standard and summer time, so for part of the year you may actually want ADT to GMT. Always check which label a region is currently using before you schedule.