Does it handle Daylight Saving Time?

Yes, the tool automatically adjusts for Daylight Saving Time based on the specific date you select, ensuring accurate conversions year-round.

Can I add multiple cities?

Yes, you can add as many cities as you need to the dashboard to compare times across your entire global network simultaneously.

MDT to IRST

+9h 30m

MDT

MDTSOURCE

UTC-06:00☀ DST active

HH12

MM00

12:00 (24-hr)

12 AM6 AM12 PM6 PM12 AM

IRST

UTC+03:30

HH09

MM30

21:30 (24-hr)

12 AM6 AM12 PM6 PM12 AM

Quick Reference

Time Conversion Table

MDT

IRST

12:00 AM

9:30 AM

2:00 AM

11:30 AM

4:00 AM

1:30 PM

6:00 AM

3:30 PM

8:00 AM

5:30 PM

10:00 AM

7:30 PM

12:00 PM

9:30 PM

2:00 PM

11:30 PM

4:00 PM

1:30 AM+1

6:00 PM

3:30 AM+1

8:00 PM

5:30 AM+1

10:00 PM

7:30 AM+1

Green rows indicate typical business hours (9 AM - 5 PM)

MDT and IRST on the World Map

The map below highlights the MDT (Mountain Daylight Time) and IRST (Iran Standard Time) timezone regions across the globe.

MDT Zone

→

IRST Zone

Explore all world timezones interactively →

MDT – Mountain Daylight Time

UTC-06:00

Mountain Daylight Time (MDT) is the daylight saving offset in the Mountain Time Zone, 6 hours behind UTC.

Countries in MDT

United States (Mountain)Canada (Alberta)

Major Cities in MDT

DenverCalgaryEdmontonSalt Lake CityBoise

Key Facts about MDT

•MDT shares the same offset as CST (UTC-06:00).
•Arizona does not switch to MDT, remaining on MST.

Daylight Saving:Yes – switches to MST

Learn more about MDT on Wikipedia

IRST – Iran Standard Time

UTC+03:30

Iran Standard Time (IRST) is the time zone for Iran, 3 hours and 30 minutes ahead of UTC.

Countries in IRST

Iran

Major Cities in IRST

TehranIsfahanMashhadTabrizShirazKaraj

Key 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).
•Tehran has a metropolitan population of over 16 million.

Daylight Saving:Yes – switches to IRDT

Learn more about IRST on Wikipedia

Comparing Time Zones: MDT and IRST

MDT runs on Mountain Daylight Time (MDT) at UTC-06:00. IRST runs on Iran Standard Time (IRST) at UTC+03:30. That puts MDT 9 hours 30 minutes ahead of IRST — a difference of +9h 30m at the current offsets.

In practice, when it is 9:00 AM in MDT it is 6:30 PM in IRST. Midnight in MDT is 9:30 AM in IRST. Neither zone observes daylight saving time, so the offset between them stays constant all year.

MDT to IRST time conversion table

MDT (MDT)	IRST (IRST)	Day
12:00 AM	9:30 AM	same day
6:00 AM	3:30 PM	same day
7:00 AM	4:30 PM	same day
8:00 AM	5:30 PM	same day
9:00 AM	6:30 PM	same day
12:00 PM	9:30 PM	same day
3:00 PM	12:30 AM	next day
5:00 PM	2:30 AM	next day
6:00 PM	3:30 AM	next day
9:00 PM	6:30 AM	next day

Why people convert MDT to IRST time

Scheduling a call from MDT to IRST: a 10:00 AM start in MDT lands at 7:30 PM in IRST, so you can confirm the slot without doing the arithmetic yourself.
Handling a +9h 30m gap: MDT and IRST 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 IRST is 6:30 PM in MDT.
Coordinating a MDT-based team with IRST 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 MDT" 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 MDT takes the early slot, the next week IRST does.

About MDT (Mountain Daylight Time)

Mountain Daylight Time (MDT) is observed during summer months in the Mountain Time Zone, except in Arizona which stays on MST year-round. MDT aligns with Central Standard Time (CST) at 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 MDT and IRST

With a +9h 30m offset there is no overlap inside a normal 9 AM – 5 PM day. IRST opens at 9:00 AM IRST, which is 6:30 PM in MDT, so real-time calls need an early-morning or late-evening slot on one side.

Business hours overlap

MDT and IRST have no shared working hours because of the +9h 30m gap. Teams need to alternate early starts or rely on asynchronous handovers.

MDT is 9 hours 30 minutes ahead of IRST (MDT UTC-06:00 → 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

MDT

☀ Currently in DST

Standard: UTC-07:00 · DST: UTC-06:00

Clocks fall back on Sun, Nov 1, 2026

IRST

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:

⏳

History of Timekeeping

From sundials to atomic clocks - 5000 years of measuring time

🌍

How Time Zones Work

UTC, offsets, and why zones don't follow straight lines

☀️

Daylight Saving Time

DST dates, which countries observe it, and the ongoing debate

Frequently Asked Questions

What is the time difference between MDT and IRST?

MDT (MDT, UTC-06:00) is 9 hours 30 minutes ahead of IRST (IRST, UTC+03:30). The gap is currently +9h 30m.

How do I convert MDT time to IRST time?

Add +9h 30m to MDT local time. For example, 9:00 AM in MDT is 6:30 PM in IRST.

What time is it in IRST right now?

IRST 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 +9h 30m offset from MDT.