IST
India Standard Time
GMT +5:30
Z
Zulu Time Zone
GMT +0

Time Difference

India Standard Time is 5 hours and 30 minutes ahead of Zulu Time Zone
9:00 pm21:00 in IST is 3:30 pm15:30 in Z

IST to Z call time
Best time for a conference call or a meeting is between 1:30pm-6pm in IST which corresponds to 8am-12:30pm in Z

9:00 pm21:00 India Standard Time (IST). Offset UTC +5:30 hours
3:30 pm15:30 Zulu Time Zone (Z). Offset UTC 0:00 hours

9:00 pm21:00 IST / 3:30 pm15:30 Z

IST Z
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
  • Iran Standard Time - UTC +3:30

Zulu Time Zone

Offset: Z is 0 hours ahead Greenwich Mean Time (GMT) and is used in Military

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.

Z representations, usage and related time zones

W3C/ISO-8601: International standard covering representation and exchange of dates and time-related data
  • Z - is the zone designator for the zero UTC/GMT offset, also known as 'Zulu' time
  • +00 - basic short
  • +0000 - basic
  • +00:00 - extended
Email/RFC-2822: Internet Message Format Date Standard, typically used for timestamps in email headers
  • +0000 - sign character (+) followed by a four digit time providing hours (00) and minutes (00) of the offset. Indicates zero hour and zero minutes time differences of the zero meridian.
Military/NATO: Used by the U.S. military, Chinese military and others
  • Zulu - Military abbreviation for Z
  • Z - short form of 'Zulu'
Time zones with the GMT +0 offset:
  • EGST - Eastern Greenland Summer Time
  • GMT - Greenwich Mean Time
  • WET - Western European Time
  • AZOST - Azores Summer Time
  • UTC - Universal Time Coordinated
  • WT - Western Sahara Standard Time
  • Z - Zulu Time Zone