GMT to AST time converter
Enter a time in GMT to get the matching time in AST, whether it falls on the next or previous day, and a full 24-hour table. Handy for planning calls between London in winter and Riyadh, Kuwait and Doha.
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Processing and privacy: The result is calculated inside your browser and your data is not sent to any server.
How to use it
- Enter time in gmt and day in gmt (optional).
- The result appears straight away and updates as you edit.
- Copy the result, or copy a link that keeps the same values to share it.
How it is calculated
AST time = GMT time + 3 hours, because AST is UTC+3 and GMT is UTC+0. If the result reaches 24:00 or more, subtract 24 hours and move to the next day; if it drops below 00:00, add 24 hours and move to the previous day.
Example
Inputs: Time in GMT = 22:00, Day in GMT (optional) = Thursday. Result: Time in AST: 01:00; Day change: Next day (+1); Offset difference (AST minus GMT): 3 hours.
Limits and caveats
- Fixed offsets are used: GMT = UTC+0 and AST = UTC+3, whatever the date.
- London leaves GMT for BST (UTC+1) from the last Sunday of March to the last Sunday of October; the tool does not apply that change.
- AST here is Arabia Standard Time (UTC+3), not Atlantic Standard Time (UTC-4).
Questions about this tool
What time is 09:00 GMT in AST?
09:00 GMT is 12:00 AST on the same day, because AST is 3 hours ahead of GMT.
Does daylight saving time change the result?
The tool keeps GMT at UTC+0 all year. London leaves GMT for BST (UTC+1) from the last Sunday of March to the last Sunday of October; in that period the gap between London and AST is 2 hours.
Is AST here Atlantic Standard Time?
No. Here AST means Arabia Standard Time, UTC+3, used in Riyadh, Kuwait, Doha, Manama and Baghdad. Atlantic Standard Time, used in Puerto Rico and Halifax, is UTC-4.