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London · Reykjavik · Accra
Compare working hours worldwide in the world conference planner.
Difference
AST vs GMT
UTC → UTC
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San Juan · Barbados · Halifax (winter)
GMT to AST converter
Convert GMT to AST time now
Free GMT to AST converter. See Greenwich Mean Time and Atlantic Standard Time side by side. Live clocks, a 4 hours gap, meeting hours, and a full-day chart for London and San Juan.
Etc/UTC
—
GMT → AST
To · Atlantic Standard Time
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America/Puerto_Rico
Interactive diagram
Watch GMT convert into AST
Drag the GMT hour. Watch the Atlantic clock change.
GMT
9:00 AM GMT
—
AST ← GMT
Atlantic
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Full-day chart
GMT to AST hourly conversion chart
Full-day table. Tap a row to copy. Labels follow daylight saving.
| GMT | Atlantic | UTC offsets |
|---|
Meeting times
Best GMT to AST meeting window
Find hours that work on both sides. Then save the slot to your calendar.
Follow along
Step-by-step GMT to AST conversion
Four short steps to convert any GMT time to AST.
Choose GMT time
Select any hour in Greenwich Mean Time. Smart mode uses Etc/UTC.
GMT to AST conversion guide
GMT to AST conversion guide
This GMT to AST converter shows Atlantic Standard Time (UTC−4) for any Greenwich Mean Time (UTC±0) time. Use it to schedule between London and San Juan. Choose Smart DST for live city clocks. Choose Fixed mode when you only want the GMT and AST labels.
GMT
GMT
UTC±0
London · Reykjavik · Accra
GMT vs AST—
Atlantic
AST
UTC−4
San Juan · Barbados · Halifax (winter)
What is GMT to AST conversion?
GMT to AST conversion turns a GMT clock into the matching AST time. Use it for calls, travel, and teams in London and San Juan.
GMT to AST time difference
AST is 4 hours behind GMT. Subtract 4 hours from the GMT time to get AST. The live clocks at the top show the current GMT to AST gap.
GMT vs AST
GMT is UTC±0. AST is UTC−4. They are different names. If a region uses daylight saving, check the live labels.
GMT to AST now / current time
Need gmt to ast right now? Read the live clocks, or tap Use current time for an instant GMT → AST result.
GMT to AST time difference
Season / context — tap to explore
See how daylight saving can change this pair.
GMT—
—GMT → AST
Atlantic—
Quick answers
GMT
Greenwich Mean Time (GMT)
UTC±0
Same as UTC+0 here. London often uses BST in summer.
- Cities: London · Reykjavik · Accra
- City clock: Etc/UTC
- Fixed GMT: UTC±0
- On this page it pairs with AST (UTC−4)
Atlantic
Atlantic Standard Time (AST)
UTC−4
Atlantic Standard Time (AST) is UTC−4. Smart DST uses America/Puerto_Rico for cities such as San Juan · Barbados · Halifax (winter).
- Cities: San Juan · Barbados · Halifax (winter)
- City clock: America/Puerto_Rico
- Fixed AST: UTC−4
- From GMT: AST is 4 hours behind GMT
GMT to AST FAQ