Chicago to Iran
+8h 30mChicago
CDTSOURCEIran
IRSTGreen rows indicate typical business hours (9 AM - 5 PM)
CDT and IRST on the World Map
The map below highlights the CDT (Central Standard Time) and IRST (Iran Standard Time) timezone regions across the globe.
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.
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.
About Chicago
WikipediaChicago operates on Central Time (CST/CDT), 1 hour behind New York. Home to CME and CBOE, Chicago is a global center for derivatives trading.
The Chicago Board of Trade is the world's oldest futures and options exchange.
Chicago vs Iran: Offsets, DST and Best Call Times
Chicago runs on Central Daylight Time (CDT) at UTC-05:00, currently observing daylight saving time. Iran runs on Iran Standard Time (IRST) at UTC+03:30. That puts Chicago 8 hours 30 minutes ahead of Iran — a difference of +8h 30m at the current offsets.
In practice, when it is 9:00 AM in Chicago it is 5:30 PM in Iran. Midnight in Chicago is 8:30 AM in Iran.Chicago observes daylight saving time while Iran does not, so the gap narrows or widens by an hour part of the year.
Chicago to Iran time conversion table
| Chicago (CDT) | Iran (IRST) | Day |
|---|---|---|
| 12:00 AM | 8:30 AM | same day |
| 6:00 AM | 2:30 PM | same day |
| 7:00 AM | 3:30 PM | same day |
| 8:00 AM | 4:30 PM | same day |
| 9:00 AM | 5:30 PM | same day |
| 12:00 PM | 8:30 PM | same day |
| 3:00 PM | 11:30 PM | same day |
| 5:00 PM | 1:30 AM | next day |
| 6:00 PM | 2:30 AM | next day |
| 9:00 PM | 5:30 AM | next day |
Why people convert Chicago to Iran time
- Scheduling a call from Chicago to Iran: a 10:00 AM start in Chicago lands at 6:30 PM in Iran, so you can confirm the slot without doing the arithmetic yourself.
- Handling a +8h 30m gap: Chicago and Iran 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 Iran is 5:30 PM in Chicago.
- Keeping family and friends in sync: knowing that 8:00 PM in Chicago is 4:30 AM in Iran makes it easy to avoid calling at 3 AM.
- Always state the zone abbreviation, not just the hour. "3:00 PM CDT" is unambiguous; "3 PM" across a +8h 30m gap is not.
- With a +8h 30m gap there is no shared 9-to-5 window, so alternate the early start: one week Chicago takes the early slot, the next week Iran does.
- Chicago: Clocks fall back on Sun, Nov 1, 2026. Re-check this page after that date because the offset changes and so does the +8h 30m gap.
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.
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.
Best time to call between Chicago and Iran
With a +8h 30m offset there is no overlap inside a normal 9 AM – 5 PM day. Iran opens at 9:00 AM IRST, which is 5:30 PM in Chicago, so real-time calls need an early-morning or late-evening slot on one side.
Business hours overlap
Chicago and Iran have no shared working hours because of the +8h 30m gap. Teams need to alternate early starts or rely on asynchronous handovers.
Chicago is 8 hours 30 minutes ahead of Iran (CDT UTC-05:00 → IRST UTC+03:30). 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
Chicago
☀ Currently in DST
Standard: UTC-06:00 · DST: UTC-05:00
Clocks fall back on Sun, Nov 1, 2026
Iran
Does not observe DST
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 Chicago and Iran?
Chicago (CDT, UTC-05:00) is 8 hours 30 minutes ahead of Iran (IRST, UTC+03:30). The gap is currently +8h 30m.
How do I convert Chicago time to Iran time?
Add +8h 30m to Chicago local time. For example, 9:00 AM in Chicago is 5:30 PM in Iran.
What time is it in Iran right now?
Iran uses IRST at UTC+03:30. Use the live converter at the top of this page — it updates in real time and already accounts for the +8h 30m offset from Chicago.
What is the best time to call Iran from Chicago?
There is no shared working-hours window because of the +8h 30m gap. The closest option is 1:00 PM in Chicago, which is 9:30 PM in Iran.
Which is ahead, Chicago or Iran?
Chicago is 8 hours 30 minutes ahead of Iran. When it is 12:00 PM in Chicago it is 8:30 PM in Iran.
Do Chicago and Iran use different time zones?
Chicago (USA) uses CDT at UTC-05:00, while Iran (Iran) uses IRST at UTC+03:30. The IANA identifiers are America/Chicago and Asia/Tehran.
Does daylight saving time affect the Chicago–Iran difference?
Yes at the moment: Chicago is on daylight saving time and Iran is not, so the +8h 30m gap shifts by an hour when exactly one of them changes clocks.
Which other cities share Chicago's time zone?
CDT also covers Chicago, Houston, Dallas, San Antonio, Mexico City, Austin, Winnipeg, Memphis and 6 more.
Which countries use CDT, Chicago's zone?
CDT is used in United States (Central), Canada (Manitoba, Saskatchewan), Mexico, Guatemala, Honduras, El Salvador, Costa Rica, Nicaragua and 1 more.
Is there a day difference between Chicago and Iran?
Not normally. The +8h 30m gap only pushes the date over for late-evening times.
What is the time difference between Chicago and Iran?
Iran is +8h 30m from Chicago.
What timezone is Chicago in?
Chicago operates on Central Time (CST/CDT), 1 hour behind New York. Home to CME and CBOE, Chicago is a global center for derivatives trading.
What timezone is Iran in?
Iran operates on its local timezone.
What are the business hours in Chicago?
Standard business hours in Chicago are 8:00 AM - 5:00 PM CST.
Which countries use CST (Central Standard Time)?
CST is used in United States (Central), Canada (Manitoba, Saskatchewan), Mexico, Guatemala, Honduras, El Salvador, and 3 more countries.
Does CST observe daylight saving time?
Yes, CST switches to CDT during summer months.
What are some interesting facts about CST?
CST covers 20 US states fully or partially. Chicago and Houston are the two largest cities in the Central Time Zone.
Which cities are in the IRST timezone?
Major cities in the IRST timezone include Tehran, Isfahan, Mashhad, Tabriz, Shiraz, Karaj.
What is the UTC offset for IRST?
Iran Standard Time (IRST) is at UTC+03:30. During daylight saving time, it shifts to IRDT.
What should I know about the IRST timezone?
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).
When is it midnight in Chicago, what time is it in Iran?
When it is 12:00 AM (midnight) in Chicago (CST), it is +8h 30m later in Iran (IRST).
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