IRST
Iran Standard Time
GMT +3:30
GMT/BST
Greenwich Mean Time
GMT +0
BST automatically adjusted to GMT time zone, that is in use

Time Difference

Iran Standard Time is 3 hours and 30 minutes ahead of Greenwich Mean Time
So 5:30 pm17:30 in IRST is 2:00 pm14:00 in GMT

5:30 pm17:30 Iran Standard Time (IRST). Offset UTC +3:30 hours
2:00 pm14:00 Greenwich Mean Time (GMT). Offset UTC 0:00 hours

5:30 pm17:30 IRST / 2:00 pm14:00 GMT

IRST GMT
12am (midnight) 8:30 pm
1am 9:30 pm
2am 10:30 pm
3am 11:30 pm
4am 12:30 am
5am 1:30 am
6am 2:30 am
7am 3:30 am
8am 4:30 am
9am 5:30 am
10am 6:30 am
11am 7:30 am
12pm (noon) 8:30 am
1pm 9:30 am
2pm 10:30 am
3pm 11:30 am
4pm 12:30 pm
5pm 1:30 pm
6pm 2:30 pm
7pm 3:30 pm
8pm 4:30 pm
9pm 5:30 pm
10pm 6:30 pm
11pm 7:30 pm
0:00 20:30
1:00 21:30
2:00 22:30
3:00 23:30
4:00 0:30
5:00 1:30
6:00 2:30
7:00 3:30
8:00 4:30
9:00 5:30
10:00 6:30
11:00 7:30
12:00 8:30
13:00 9:30
14:00 10:30
15:00 11:30
16:00 12:30
17:00 13:30
18:00 14:30
19:00 15:30
20:00 16:30
21:00 17:30
22:00 18:30
23:00 19:30

British Summer Time

Offset: BST is 1 hour ahead Greenwich Mean Time (GMT) and is used in Europe

Countries: It is used in following countries: Britain (UK), Guernsey, Isle of Man, Jersey

Principal Cities: The largest city in the BST timezone is London from United Kingdom with population about 7.557 million people. Other major cities in the area are Birmingham, Glasgow, Liverpool, Saint Helier

Greenwich Mean Time (GMT) originally referred to the mean solar time at the Royal Observatory in Greenwich, London. It is now often used to refer to Coordinated Universal Time (UTC) when this is viewed as a time zone, and in casual use for the most parts it is the same. In military GMT is known as Zulu time.Greenwich Mean Time was the same as Universal Time (UT), until the introduction of UTC in 1972 a standard astronomical concept used in many technical fields.

BST Time Zone Geo Map
BST timezone map
BST representations, usage and related time zones

W3C/ISO-8601: International standard covering representation and exchange of dates and time-related data
  • +01 - basic short
  • +0100 - basic
  • +01:00 - extended

Email/RFC-2822: Internet Message Format Date Standard, typically used for timestamps in email headers
  • +0100 - sign character (+) followed by a four digit time providing hours (01) and minutes (00) of the offset. Indicates one hour and zero minutes time differences to the east of the zero meridian.

Military/NATO: Used by the U.S. military, Chinese military and others
  • Alpha - Military abbreviation for BST
  • A - short form of 'Alpha'

IANA/Olson: Reflects BST time zone boundaries defined by political bodies, primarily intended for use with computer programs and operating systems
  • Europe/Belfast
  • Europe/Guernsey
  • Europe/Isle_of_Man
  • Europe/Jersey
  • Europe/London
  • GB
  • GB-Eire

BST Abbreviation: Several time zones share BST abbreviation and it could refer to these time zones

  • British Summer Time - UTC +1
  • Bangladesh Standard Time - UTC +6
  • Bougainville Standard Time - UTC +11

Time zones with the GMT +1 offset:

  • 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
  • GMT - GMT
  • +01 -