IST
India Standard Time
GMT +5:30
12am
3am
6am
9am
12pm
3pm
6pm
9pm
BST
Bougainville Standard Time
GMT +11
12am
3am
6am
9am
12pm
3pm
6pm
9pm

Quick answers

IST is 5 hours and 30 minutes behind BST. IST uses GMT +5:30, and BST uses GMT +11 for this comparison.

For example, 5:30 pm IST is 11:00 pm BST. Use the converter above to adjust the date or time and create a shareable meeting link.

Best meeting overlap: 9am-11:30am IST, which is 2:30pm-5pm BST.

Compare IST time with BST time, including current local time, UTC offsets, time difference, daylight saving changes, working hours, and shareable meeting times.

Time Difference

India Standard Time is 5 hours and 30 minutes behind Bougainville Standard Time
5:30 pm17:30 in IST is 11:00 pm23:00 in BST

IST to BST call time
Best time for a conference call or a meeting is between 9am-11:30am in IST which corresponds to 2:30pm-5pm in BST

5:30 pm17:30 India Standard Time (IST). Offset UTC +5:30 hours
11:00 pm23:00 Bougainville Standard Time (BST). Offset UTC +11:00 hours

5:30 pm17:30 IST / 11:00 pm23:00 BST

ISTBST
12am (midnight)5:30 am
1am6:30 am
2am7:30 am
3am8:30 am
4am9:30 am
5am10:30 am
6am11:30 am
7am12:30 pm
8am1:30 pm
9am2:30 pm
10am3:30 pm
11am4:30 pm
12pm (noon)5:30 pm
1pm6:30 pm
2pm7:30 pm
3pm8:30 pm
4pm9:30 pm
5pm10:30 pm
6pm11:30 pm
7pm12:30 am
8pm1:30 am
9pm2:30 am
10pm3:30 am
11pm4:30 am
00:0005:30
01:0006:30
02:0007:30
03:0008:30
04:0009:30
05:0010:30
06:0011:30
07:0012:30
08:0013:30
09:0014:30
10:0015:30
11:0016:30
12:0017:30
13:0018:30
14:0019:30
15:0020:30
16:0021:30
17:0022:30
18:0023:30
19:0000:30
20:0001:30
21:0002:30
22:0003:30
23:0004:30

India Standard Time

Offset: IST is 5 hours and 30 minutes ahead Greenwich Mean Time (GMT) and is used in Asia

Countries using this time zone: India

Principal Cities: The largest city in the IST time zone is Mumbai in India, with about 12.692 million people. Other major cities in this time zone include Delhi, Bangalore, Kolkata, Chennai.

Daylight Saving: Clocks in India Standard Time (IST) do not change for daylight saving time, so IST stays the same throughout the year. Other time zones may set clocks forward in summer and back in winter.

IST Time Zone Geo Map
IST timezone map

IST representations, usage and related time zones

W3C/ISO-8601: International standard covering representation and exchange of dates and time-related data
  • +0530 - basic
  • +05:30 - extended
Email/RFC-2822: Internet Message Format Date Standard, typically used for timestamps in email headers
  • +0530 - sign character (+) followed by a four digit time providing hours (05) and minutes (30) of the offset. Indicates an offset of five hours and thirty minutes to the east of the zero meridian.
IANA/Olson: Reflects IST time zone boundaries defined by political bodies, primarily intended for use with computer programs and operating systems
  • Asia/Calcutta
  • Asia/Kolkata
IST Abbreviation: Several time zones share IST abbreviation and it could refer to these time zones
  • India Standard Time - UTC +5:30
  • Irish Standard Time - UTC +1
  • Israel Standard Time - UTC +2

Bougainville Standard Time

Offset: BST is 11 hours ahead Greenwich Mean Time (GMT) and is used in Pacific

Daylight Saving: Clocks in Bougainville Standard Time (BST) do not change for daylight saving time, so BST stays the same throughout the year. Other time zones may set clocks forward in summer and back in winter.

BST representations, usage and related time zones

W3C/ISO-8601: International standard covering representation and exchange of dates and time-related data
  • +11 - basic short
  • +1100 - basic
  • +11:00 - extended
Email/RFC-2822: Internet Message Format Date Standard, typically used for timestamps in email headers
  • +1100 - sign character (+) followed by a four digit time providing hours (11) and minutes (00) of the offset. Indicates an offset of eleven hours to the east of the zero meridian.
Military/NATO: Used by the U.S. military, Chinese military and others
  • Lima - Military abbreviation for BST
  • L - short form of 'Lima'
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 +11 offset:
  • AEDT - Australian Eastern Daylight Time
  • BST - Bougainville Standard Time
  • KOST - Kosrae Time
  • L - Lima Time Zone
  • LHDT - Lord Howe Daylight Time
  • MAGT - Magadan Time
  • NCT - New Caledonia Time
  • NFT - Norfolk Time
  • PETT - Kamchatka Time
  • PONT - Pohnpei Standard Time
  • SBT - Solomon IslandsTime
  • VLAST - Vladivostok Summer Time
  • VUT - Vanuatu Time