IST
India Standard Time
GMT +5:30
GMT/IST
Greenwich Mean Time
GMT +0
IST automatically adjusted to GMT time zone, that is in use

Time Difference

India Standard Time is 5 hours and 30 minutes ahead of Greenwich Mean Time
So 4:00 pm16:00 in IST is 10:30 am10:30 in GMT

4:00 pm16:00 India Standard Time (IST). Offset UTC +5:30 hours
10:30 am10:30 Greenwich Mean Time (GMT). Offset UTC 0:00 hours

4:00 pm16:00 IST / 10:30 am10:30 GMT

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

India Standard Time

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

Countries: It is used in following countries: India

Principal Cities: The largest city in the IST timezone is Mumbai from India with population about 12.692 million people. Other major cities in the area are Delhi, Bangalore, Kolkata, Chennai

Daylight Saving: India Standard Time (IST) is not adjusted for daylight saving therefore IST remains the same through out the year. This means, unlike some time zones where the clock is set forward by one hour every summer and backward by one hour during winter to adjust for daylight saving, India Standard Time remains the same

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 five hour and thirty minutes time differences 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


Irish Standard Time

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

Countries: It is used in following countries: Ireland

Principal Cities: The largest city in the IST timezone is Dublin from Ireland with population about 1.024 million people. Other major cities in the area are Cork, Dun Laoghaire, Luimneach, Gaillimh

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.

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
  • +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 IST
  • A - short form of 'Alpha'

IANA/Olson: Reflects IST time zone boundaries defined by political bodies, primarily intended for use with computer programs and operating systems
  • Eire
  • Europe/Dublin

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

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 - Mitteleurop√ɬ§ische Zeit
  • WAT - West Africa Time
  • WST - Western Sahara Summer Time
  • BMT - Biel Mean Time
  • +01 -