MST to Tehran
+10h 30mMST
MSTSOURCETehran
IRSTGreen rows indicate typical business hours (9 AM - 5 PM)
MST and IRST on the World Map
The map below highlights the MST (Mountain Standard Time) and IRST (Iran Standard Time) timezone regions across the globe.
MST – Mountain Standard Time
UTC-07:00Mountain Standard Time (MST) is the time zone for the Mountain region of North America, 7 hours behind UTC.
- •Arizona does not observe daylight saving time, staying on MST year-round.
- •The Navajo Nation in Arizona does observe DST, unlike the rest of the state.
- •Denver, the 'Mile High City', is the largest city fully in MST.
- •MST covers 6 US states entirely and parts of several others.
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 Tehran
WikipediaTehran operates on Iran Standard Time (IRST), UTC+3:30. Iran's unique half-hour offset makes Tehran time distinctive for regional business coordination.
Iran Standard Time (IRST) is one of few timezones with a 30-minute offset (UTC+3:30).
Time Conversion Guide: MST to Tehran
MST runs on Mountain Standard Time (MST) at UTC-07:00. Tehran runs on Iran Standard Time (IRST) at UTC+03:30. That puts MST 10 hours 30 minutes ahead of Tehran — a difference of +10h 30m at the current offsets.
In practice, when it is 9:00 AM in MST it is 7:30 PM in Tehran. Midnight in MST is 10:30 AM in Tehran. Neither zone observes daylight saving time, so the offset between them stays constant all year.
MST to Tehran time conversion table
| MST (MST) | Tehran (IRST) | Day |
|---|---|---|
| 12:00 AM | 10:30 AM | same day |
| 6:00 AM | 4:30 PM | same day |
| 7:00 AM | 5:30 PM | same day |
| 8:00 AM | 6:30 PM | same day |
| 9:00 AM | 7:30 PM | same day |
| 12:00 PM | 10:30 PM | same day |
| 3:00 PM | 1:30 AM | next day |
| 5:00 PM | 3:30 AM | next day |
| 6:00 PM | 4:30 AM | next day |
| 9:00 PM | 7:30 AM | next day |
Why people convert MST to Tehran time
- Scheduling a call from MST to Tehran: a 10:00 AM start in MST lands at 8:30 PM in Tehran, so you can confirm the slot without doing the arithmetic yourself.
- Handling a +10h 30m gap: MST and Tehran 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 Tehran is 7:30 PM in MST.
- Watching a live event or market open: MST viewers need 7:30 PM in Tehran to catch a 9:00 AM start there, and 1:30 PM if the event is anchored to MST.
- Always state the zone abbreviation, not just the hour. "3:00 PM MST" is unambiguous; "3 PM" across a +10h 30m gap is not.
- With a +10h 30m gap there is no shared 9-to-5 window, so alternate the early start: one week MST takes the early slot, the next week Tehran does.
About MST (Mountain Standard Time)
Mountain Standard Time (MST) covers the Rocky Mountain region of the United States and Canada. Arizona is notable for not observing daylight saving time, staying on MST year-round (except the Navajo Nation). The time zone includes major cities like Denver, Phoenix, Calgary, and Salt Lake City. During summer, most areas switch to Mountain Daylight Time (MDT, UTC-06:00).
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 MST and Tehran
With a +10h 30m offset there is no overlap inside a normal 9 AM – 5 PM day. Tehran opens at 9:00 AM IRST, which is 7:30 PM in MST, so real-time calls need an early-morning or late-evening slot on one side.
Business hours overlap
MST and Tehran have no shared working hours because of the +10h 30m gap. Teams need to alternate early starts or rely on asynchronous handovers.
MST is 10 hours 30 minutes ahead of Tehran (MST UTC-07:00 → 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
MST
☀ Currently in DST
Standard: UTC-07:00 · DST: UTC-06:00
Clocks fall back on Sun, Nov 1, 2026
Tehran
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 MST and Tehran?
MST (MST, UTC-07:00) is 10 hours 30 minutes ahead of Tehran (IRST, UTC+03:30). The gap is currently +10h 30m.
How do I convert MST time to Tehran time?
Add +10h 30m to MST local time. For example, 9:00 AM in MST is 7:30 PM in Tehran.
What time is it in Tehran right now?
Tehran 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 +10h 30m offset from MST.
What is the best time to call Tehran from MST?
There is no shared working-hours window because of the +10h 30m gap. The closest option is 1:00 PM in MST, which is 11:30 PM in Tehran.
Which is ahead, MST or Tehran?
MST is 10 hours 30 minutes ahead of Tehran. When it is 12:00 PM in MST it is 10:30 PM in Tehran.
Do MST and Tehran use different time zones?
MST uses MST at UTC-07:00, while Tehran (Iran) uses IRST at UTC+03:30. The IANA identifiers are America/Denver and Asia/Tehran.
Does daylight saving time affect the MST–Tehran difference?
Neither zone observes daylight saving time, so the +10h 30m offset between MST and Tehran is fixed all year.
Which other cities share MST's time zone?
MST also covers Denver, Phoenix, Salt Lake City, Calgary, Edmonton, Albuquerque, El Paso, Tucson and 2 more.
Which countries use MST, MST's zone?
MST is used in United States (Mountain), Canada (Alberta), Mexico (Chihuahua, Sonora).
Is there a day difference between MST and Tehran?
Not normally. The +10h 30m gap only pushes the date over for late-evening times.
What is the time difference between MST and Tehran?
Tehran is +10h 30m from MST.
What timezone is MST in?
MST operates on its local timezone.
What timezone is Tehran in?
Tehran operates on Iran Standard Time (IRST), UTC+3:30. Iran's unique half-hour offset makes Tehran time distinctive for regional business coordination.
What are the business hours in Tehran?
Standard business hours in Tehran are 8:00 AM - 4:00 PM IRST.
Which countries use MST (Mountain Standard Time)?
MST is used in United States (Mountain), Canada (Alberta), Mexico (Chihuahua, Sonora).
Does MST observe daylight saving time?
Yes, MST switches to MDT during summer months.
What are some interesting facts about MST?
Arizona does not observe daylight saving time, staying on MST year-round. The Navajo Nation in Arizona does observe DST, unlike the rest of the state.
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 MST, what time is it in Tehran?
When it is 12:00 AM (midnight) in MST (MST), it is +10h 30m later in Tehran (IRST).
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