BST to IRST Converter
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Quick answers
Selected conversion
1:00 pm13:00 BST (UTC+1), Oct 13, 2026 = 3:30 pm15:30 IRST (UTC+3:30), Oct 13, 2026
BST is 2 hours and 30 minutes behind IRST.
BST and IRST examples
These examples always use BST (UTC+1) and IRST (UTC+3:30). They stay the same when you change the date or time above. The selected conversion may differ when daylight saving time applies.
BST is 2 hours and 30 minutes behind IRST.
How the time difference changes
For most of the year, BST is 2 hours and 30 minutes behind IRST. From Oct 25, 2026 to Mar 28, 2027, GMT is 3 hours and 30 minutes behind IRST.
For most of the year, working hours of 9:00 am to 5:00 pm in BST correspond to 11:30 am to 7:30 pm in IRST. At other times of the year, working hours of 9:00 am to 5:00 pm in GMT correspond to 12:30 pm to 8:30 pm in IRST.For most of the year, working hours of 09:00 to 17:00 in BST correspond to 11:30 to 19:30 in IRST. At other times of the year, working hours of 09:00 to 17:00 in GMT correspond to 12:30 to 20:30 in IRST.
Compare BST time with IRST time, including current local time, UTC offsets, time difference, daylight saving changes, working hours, and shareable meeting times.
Time Difference
British Summer Time is 2 hours and 30 minutes behind Iran Standard Time.
1:00 pm13:00 in BST is 3:30 pm15:30 in IRST
BST to IRST call time
Best time for a conference call or a meeting is between 9am-2:30pm09:00-14:30 in BST which corresponds to 11:30am-5pm11:30-17:00 in IRST
1:00 pm13:00 British Summer Time (BST). Offset UTC +1:00 hour
3:30 pm15:30 Iran Standard Time (IRST). Offset UTC +3:30 hours
1:00 pm13:00 BST / 3:30 pm15:30 IRST
Choose an hour to update the converter. Day labels such as “next day” or “+1” are relative to the selected date in the first column. Use Up and Down arrow keys, Home or End to move between hours, then Enter or Space to select.
| BST | IRST |
|---|---|
| 2:30am | |
| 3:30am | |
| 4:30am | |
| 5:30am | |
| 6:30am | |
| 7:30am | |
| 8:30am | |
| 9:30am | |
| 10:30am | |
| 11:30am | |
| 12:30pm | |
| 1:30pm | |
| 2:30pm | |
| 3:30pm | |
| 4:30pm | |
| 5:30pm | |
| 6:30pm | |
| 7:30pm | |
| 8:30pm | |
| 9:30pm | |
| 10:30pm | |
| 11:30pm | |
| 12:30am next day | |
| 1:30am next day | |
| 02:30 | |
| 03:30 | |
| 04:30 | |
| 05:30 | |
| 06:30 | |
| 07:30 | |
| 08:30 | |
| 09:30 | |
| 10:30 | |
| 11:30 | |
| 12:30 | |
| 13:30 | |
| 14:30 | |
| 15:30 | |
| 16:30 | |
| 17:30 | |
| 18:30 | |
| 19:30 | |
| 20:30 | |
| 21:30 | |
| 22:30 | |
| 23:30 | |
| 00:30 next day | |
| 01:30 next day |
British Summer Time
Offset: BST is 1 hour ahead of Greenwich Mean Time (GMT).
Countries using this time zone: Britain (UK), Guernsey, Isle of Man, Jersey
Principal Cities: The largest city in the BST time zone is London in the United Kingdom, with about 8.962 million people. Other major cities in this time zone include Birmingham, Glasgow, Manchester, Sheffield.
Today all shaded areas are on BST.
Daylight Saving: British Summer Time (BST) is a daylight saving/summer time zone. During winter, some places set clocks back one hour and observe Greenwich Mean Time (GMT).
Start: British Summer Time (BST) started on Sunday, March 29, 2026 at 1:00 am01:00 local time and clocks were set one hour forward to Sunday, March 29, 2026, 2:00 am02:00. Daylight saving starts annually on the last Sunday of March.
End: British Summer Time (BST) ends on Sunday, October 25, 2026 at 2:00 am02:00 local time and clocks are set one hour back to Sunday, October 25, 2026, 1:00 am01:00 local standard time instead. Daylight saving ends annually on the last Sunday of October.
BST representations, usage and related time zones
- +01 - basic short
- +0100 - basic
- +01:00 - extended
- +0100 - sign character (+) followed by a four digit time providing hours (01) and minutes (00) of the offset. Indicates an offset of one hour to the east of the zero meridian.
- Alpha - Military abbreviation for BST
- A - short form of 'Alpha'
- Europe/Belfast
- Europe/Guernsey
- Europe/Isle_of_Man
- Europe/Jersey
- Europe/London
- GB
- GB-Eire
- British Summer Time - UTC +1
- Bangladesh Standard Time - UTC +6
- Bougainville Standard Time - UTC +11
- BST - British Summer Time
- CET - Central European Time
- IST - Irish Standard Time
- WEST - Western European Summer Time
- A - Alpha Time Zone
- CET - Central European Time
- MEZ - Mitteleuropäische Zeit
- WAT - West Africa Time
- WST - Western Sahara Summer Time
- BMT - Biel Mean Time
Iran Standard Time
Offset: IRST is 3 hours and 30 minutes ahead of Greenwich Mean Time (GMT).
Countries using this time zone: Iran
Principal Cities: The largest city in the IRST time zone is Tehran in Iran, with about 7.153 million people. Other major cities in this time zone include Mashhad, Isfahan, Karaj, Tabriz.
Daylight Saving: Clocks in Iran Standard Time (IRST) do not change for daylight saving time, so IRST stays the same throughout the year. Other time zones may set clocks forward in summer and back in winter; see upcoming clock changes worldwide.
IRST representations, usage and related time zones
- +0330 - basic
- +03:30 - extended
- +0330 - sign character (+) followed by a four digit time providing hours (03) and minutes (30) of the offset. Indicates an offset of three hours and thirty minutes to the east of the zero meridian.