IRST
Iran Standard Time
GMT +3:30
12am
3am
6am
9am
12pm
3pm
6pm
9pm
D
Delta Time Zone
GMT +4
12am
3am
6am
9am
12pm
3pm
6pm
9pm

Quick answers

IRST is 30 minutes behind D. IRST uses GMT +3:30, and D uses GMT +4 for this comparison.

For example, 3:30 pm IRST is 4:00 pm D. Use the converter above to adjust the date or time and create a shareable meeting link.

Best meeting overlap: 9am-4:30pm IRST, which is 9:30am-5pm D.

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

Time Difference

Iran Standard Time is 0 hours and 30 minutes behind Delta Time Zone
3:30 pm15:30 in IRST is 4:00 pm16:00 in D

IRST to D call time
Best time for a conference call or a meeting is between 9am-4:30pm in IRST which corresponds to 9:30am-5pm in D

3:30 pm15:30 Iran Standard Time (IRST). Offset UTC +3:30 hours
4:00 pm16:00 Delta Time Zone (D). Offset UTC +4:00 hours

3:30 pm15:30 IRST / 4:00 pm16:00 D

IRSTD
12am (midnight)12:30 am
1am1:30 am
2am2:30 am
3am3:30 am
4am4:30 am
5am5:30 am
6am6:30 am
7am7:30 am
8am8:30 am
9am9:30 am
10am10:30 am
11am11:30 am
12pm (noon)12:30 pm
1pm1:30 pm
2pm2:30 pm
3pm3:30 pm
4pm4:30 pm
5pm5:30 pm
6pm6:30 pm
7pm7:30 pm
8pm8:30 pm
9pm9:30 pm
10pm10:30 pm
11pm11:30 pm
00:0000:30
01:0001:30
02:0002:30
03:0003:30
04:0004:30
05:0005:30
06:0006:30
07:0007:30
08:0008:30
09:0009:30
10:0010:30
11:0011:30
12:0012:30
13:0013:30
14:0014:30
15:0015:30
16:0016:30
17:0017:30
18:0018:30
19:0019:30
20:0020:30
21:0021:30
22:0022:30
23:0023:30

Iran Standard Time

Offset: IRST is 3 hours and 30 minutes ahead Greenwich Mean Time (GMT) and is used in Asia

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.

IRST Time Zone Geo Map
IRST timezone map

IRST representations, usage and related time zones

W3C/ISO-8601: International standard covering representation and exchange of dates and time-related data
  • +0330 - basic
  • +03:30 - extended
Email/RFC-2822: Internet Message Format Date Standard, typically used for timestamps in email headers
  • +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.

Delta Time Zone

Offset: D is 4 hours ahead Greenwich Mean Time (GMT) and is used in Military

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

D representations, usage and related time zones

W3C/ISO-8601: International standard covering representation and exchange of dates and time-related data
  • +04 - basic short
  • +0400 - basic
  • +04:00 - extended
Email/RFC-2822: Internet Message Format Date Standard, typically used for timestamps in email headers
  • +0400 - sign character (+) followed by a four digit time providing hours (04) and minutes (00) of the offset. Indicates an offset of four hours to the east of the zero meridian.
Military/NATO: Used by the U.S. military, Chinese military and others
  • Delta - Military abbreviation for D
  • D - short form of 'Delta'
Time zones with the GMT +4 offset:
  • KUYT - Kuybyshev Time
  • MSD - Moscow Daylight Time
  • SAMT - Samara Time
  • AMT - Armenia Time
  • AZT - Azerbaijan Time
  • D - Delta Time Zone
  • GET - Georgia Standard Time
  • GST - Gulf Standard Time
  • MUT - Mauritius Time
  • RET - Reunion Time
  • SCT - Seychelles Time