Iran to CST
-9h 30mIran
IRSTSOURCECST
CSTGreen rows indicate typical business hours (9 AM - 5 PM)
IRST and CST on the World Map
The map below highlights the IRST (Iran Standard Time) and CST (Central Standard Time) timezone regions across the globe.
IRST – Iran Standard Time
UTC+03:30Iran Standard Time (IRST) is the time zone for Iran, 3 hours and 30 minutes ahead of UTC.
- •IRST is one of only a few time zones with a 30-minute offset.
- •Iran observes daylight saving time, switching to IRDT (UTC+04:30).
- •Tehran has a metropolitan population of over 16 million.
CST – Central Standard Time
UTC-06:00Central Standard Time (CST) is the time zone for the central United States, Canada, and Mexico, 6 hours behind UTC.
- •CST covers 20 US states fully or partially.
- •Chicago and Houston are the two largest cities in the Central Time Zone.
- •Mexico City, one of the world's most populous cities, operates on CST.
- •CST is 1 hour behind EST and 2 hours ahead of PST.
Time Conversion Guide: Iran to CST
Iran runs on Iran Standard Time (IRST) at UTC+03:30. CST runs on Central Standard Time (CST) at UTC-06:00. That puts Iran 9 hours 30 minutes behind CST — a difference of -9h 30m at the current offsets.
In practice, when it is 9:00 AM in Iran it is 11:30 PM in CST on the previous day. Midnight in Iran is 2:30 PM in CST. Neither zone observes daylight saving time, so the offset between them stays constant all year.
Iran to CST time conversion table
| Iran (IRST) | CST (CST) | Day |
|---|---|---|
| 12:00 AM | 2:30 PM | previous day |
| 6:00 AM | 8:30 PM | previous day |
| 7:00 AM | 9:30 PM | previous day |
| 8:00 AM | 10:30 PM | previous day |
| 9:00 AM | 11:30 PM | previous day |
| 12:00 PM | 2:30 AM | same day |
| 3:00 PM | 5:30 AM | same day |
| 5:00 PM | 7:30 AM | same day |
| 6:00 PM | 8:30 AM | same day |
| 9:00 PM | 11:30 AM | same day |
Why people convert Iran to CST time
- Scheduling a call from Iran to CST: a 10:00 AM start in Iran lands at 12:30 AM in CST, so you can confirm the slot without doing the arithmetic yourself.
- Handling a -9h 30m gap: Iran and CST have no overlap inside a normal 9-to-5 day, so real-time meetings need an early-morning or late-evening slot on one side. 9:00 AM in CST is 11:30 PM in Iran.
- Coordinating a Iran-based team with CST contacts: quoting times in the other side's local clock — not your own — removes the single biggest source of missed meetings.
- Always state the zone abbreviation, not just the hour. "3:00 PM IRST" is unambiguous; "3 PM" across a -9h 30m gap is not.
- With a -9h 30m gap there is no shared 9-to-5 window, so alternate the early start: one week Iran takes the early slot, the next week CST does.
About IRST (Iran Standard Time)
Iran Standard Time (IRST) is one of the few time zones with a 30-minute offset. Iran observes daylight saving time (IRDT, UTC+04:30) from late March to late September. Tehran, the capital, is one of the largest cities in the Middle East.
About CST (Central Standard Time)
Central Standard Time (CST) covers the central region of North America. It is the second most populous time zone in the US, including major cities like Chicago, Houston, and Dallas. CST is also used in Mexico City and much of Central America including Guatemala, Honduras, El Salvador, and Costa Rica. During summer, most of the US and Canada switch to Central Daylight Time (CDT, UTC-05:00), while Mexico and Central American countries generally remain on CST.
Best time to call between Iran and CST
With a -9h 30m offset there is no overlap inside a normal 9 AM – 5 PM day. CST opens at 9:00 AM CST, which is 11:30 PM in Iran, so real-time calls need an early-morning or late-evening slot on one side.
Business hours overlap
Iran and CST have no shared working hours because of the -9h 30m gap. Teams need to alternate early starts or rely on asynchronous handovers.
Iran is 9 hours 30 minutes behind CST (IRST UTC+03:30 → CST UTC-06:00). There is no shared 9-to-5 window, so plan around an early or late slot. Remember to re-check around daylight-saving transitions.
🕐 Daylight Saving Time Info
Iran
Does not observe DST
CST
☀ Currently in DST
Standard: UTC-06:00 · DST: UTC-05:00
Clocks fall back on Sun, Nov 1, 2026
Learn More About Time
Dive deeper into the fascinating world of timekeeping, time zones, and how they shape our global society:
Frequently Asked Questions
What is the time difference between Iran and CST?
Iran (IRST, UTC+03:30) is 9 hours 30 minutes behind CST (CST, UTC-06:00). The gap is currently -9h 30m.
How do I convert Iran time to CST time?
Add -9h 30m to Iran local time. For example, 9:00 AM in Iran is 11:30 PM in CST (previous day).
What time is it in CST right now?
CST uses CST at UTC-06:00. Use the live converter at the top of this page — it updates in real time and already accounts for the -9h 30m offset from Iran.
What is the best time to call CST from Iran?
There is no shared working-hours window because of the -9h 30m gap. The closest option is 1:00 PM in Iran, which is 3:30 AM in CST.
Which is behind, Iran or CST?
Iran is 9 hours 30 minutes behind CST. When it is 12:00 PM in Iran it is 2:30 AM in CST.
Do Iran and CST use different time zones?
Iran (Iran) uses IRST at UTC+03:30, while CST uses CST at UTC-06:00. The IANA identifiers are Asia/Tehran and America/Chicago.
Does daylight saving time affect the Iran–CST difference?
Neither zone observes daylight saving time, so the -9h 30m offset between Iran and CST is fixed all year.
Which other cities share Iran's time zone?
IRST also covers Tehran, Isfahan, Mashhad, Tabriz, Shiraz, Karaj.
Which countries use IRST, Iran's zone?
IRST is used in Iran.
Is there a day difference between Iran and CST?
Not normally. The -9h 30m gap only pushes the date over the previous day.
What is the time difference between Iran and CST?
CST is -9h 30m from Iran.
What timezone is Iran in?
Iran operates on its local timezone.
What timezone is CST in?
CST operates on its local timezone.
Which countries use IRST (Iran Standard Time)?
IRST is used in Iran.
Does IRST observe daylight saving time?
Yes, IRST switches to IRDT during summer months.
What are some interesting facts about IRST?
IRST is one of only a few time zones with a 30-minute offset. Iran observes daylight saving time, switching to IRDT (UTC+04:30).
Which cities are in the CST timezone?
Major cities in the CST timezone include Chicago, Houston, Dallas, San Antonio, Mexico City, Austin, Winnipeg, Memphis.
What is the UTC offset for CST?
Central Standard Time (CST) is at UTC-06:00. During daylight saving time, it shifts to CDT.
What should I know about the CST timezone?
CST covers 20 US states fully or partially. Chicago and Houston are the two largest cities in the Central Time Zone.
When is it midnight in Iran, what time is it in CST?
When it is 12:00 AM (midnight) in Iran (IRST), it is -9h 30m later in CST (CST).
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