AST to BST Converter
GMT is 4 hours ahead of AST. 9:00 AM AST = 1:00 PM GMT.
GMT is 4 hours ahead of AST at the moment. To convert AST to BST, add 4 hours to the AST time: 9:00 AM AST = 1:00 PM GMT.
AST (Atlantic Time) is used in Nova Scotia, New Brunswick, PEI; Puerto Rico and the Eastern Caribbean (all year). BST (British Time) is used in United Kingdom from late March to late October.
AST here is Atlantic Standard Time, not Arabia Standard Time. BST here means British Summer Time, not Bangladesh Standard Time. BST (British Summer Time) is not in force right now: United Kingdom from late March to late October is currently on GMT. This page uses whichever name applies on the date you pick, so the numbers below say GMT.
AST to BST time conversion table
AST to BST on 6 Nov 2026. Today's date. Highlighted rows are 9 AM–5 PM in both places.
| AST | BST | Day |
|---|---|---|
| 12:00 AM AST | 4:00 AM GMT | night |
| 1:00 AM AST | 5:00 AM GMT | night |
| 2:00 AM AST | 6:00 AM GMT | — |
| 3:00 AM AST | 7:00 AM GMT | — |
| 4:00 AM AST | 8:00 AM GMT | — |
| 5:00 AM AST | 9:00 AM GMT | — |
| 6:00 AM AST | 10:00 AM GMT | — |
| 7:00 AM AST | 11:00 AM GMT | — |
| 8:00 AM AST | 12:00 PM GMT | — |
| 9:00 AM AST | 1:00 PM GMT | work hours |
| 10:00 AM AST | 2:00 PM GMT | work hours |
| 11:00 AM AST | 3:00 PM GMT | work hours |
| 12:00 PM AST | 4:00 PM GMT | work hours |
| 1:00 PM AST | 5:00 PM GMT | — |
| 2:00 PM AST | 6:00 PM GMT | — |
| 3:00 PM AST | 7:00 PM GMT | — |
| 4:00 PM AST | 8:00 PM GMT | — |
| 5:00 PM AST | 9:00 PM GMT | — |
| 6:00 PM AST | 10:00 PM GMT | night |
| 7:00 PM AST | 11:00 PM GMT | night |
| 8:00 PM AST | 12:00 AM GMT | next day |
| 9:00 PM AST | 1:00 AM GMT | next day |
| 10:00 PM AST | 2:00 AM GMT | next day |
| 11:00 PM AST | 3:00 AM GMT | next day |
- Work rows — 9 AM–5 PM in both places
- Night in the destination (10 PM–6 AM)
How to convert AST to BST
Add 4 hours to the AST time to get BST.
Example: 9:00 AM AST = 1:00 PM GMT.
Across midnight: 10:00 PM AST = 2:00 AM GMT (next day). The date changes, so always check the day as well as the hour.
Time difference between AST and BST
The time difference between AST and BST is not the same all year, because the two sides change for daylight saving time on different dates. In 2026 it works out like this:
- 31 Dec 2025 – 7 Mar 2026: BST is 4 hours ahead of AST.
- 8 Mar 2026 – 27 Mar 2026: BST is 3 hours ahead of AST.
- 28 Mar 2026 – 23 Oct 2026: BST is 4 hours ahead of AST.
- 24 Oct 2026 – 31 Oct 2026: BST is 3 hours ahead of AST.
- 1 Nov 2026 – 30 Dec 2026: BST is 4 hours ahead of AST.
AST and BST during daylight saving time
- AST next changes on 14 Mar 2027: clocks go forward one hour at 01:59 local time, from AST (UTC−4) to ADT (UTC−3).
- BST next changes on 28 Mar 2027: clocks go forward one hour at 00:59 local time, from GMT (UTC+0) to BST (UTC+1).
Best time for a meeting between AST and BST
AST and BST share 4 hours of the 9 AM–5 PM working day. Any time between 9:00 AM and 1:00 PM AST lands between 1:00 PM and 5:00 PM GMT, inside working hours for both.
AST to BST FAQ
What is the time difference between AST and BST?
Right now GMT is 4 hours ahead of AST. The gap changes 5 times in 2026 because the two sides switch to daylight saving time on different dates.
What is 9 AM AST in BST?
9:00 AM AST is 1:00 PM GMT.
What is 12 PM (noon) AST in BST?
12:00 PM AST is 4:00 PM GMT.
Is BST ahead of or behind AST?
GMT is 4 hours ahead of AST, so it is later in BST than in AST.
Does AST change for daylight saving time?
Yes. AST next changes on 14 Mar 2027, when clocks go forward one hour from AST to ADT.
Does BST change for daylight saving time?
Yes. BST next changes on 28 Mar 2027, when clocks go forward one hour from GMT to BST.
What is the best time for a meeting between AST and BST?
AST and BST share 4 hours of the 9 AM–5 PM working day. Any time between 9:00 AM and 1:00 PM AST lands between 1:00 PM and 5:00 PM GMT, inside working hours for both.
Related conversions
Convert BST to AST
Convert AST to other time zones
Convert other time zones to BST
Learn more
Updated 6 November 2026. Time zone data: IANA tz database.