AEDT to MST
-18hAEDT
AEDTSOURCEMST
MSTGreen rows indicate typical business hours (9 AM - 5 PM)
AEDT and MST on the World Map
The map below highlights the AEDT (Australian Eastern Daylight Time) and MST (Mountain Standard Time) timezone regions across the globe.
AEDT – Australian Eastern Daylight Time
UTC+11:00Australian Eastern Daylight Time (AEDT, UTC+11:00) is the daylight saving period in south-eastern Australia, from October to April.
- •AEDT runs from the first Sunday in October to the first Sunday in April.
- •AEDT is one hour ahead of Australian Eastern Standard Time (AEST).
- •Queensland does not observe daylight saving, so Brisbane stays on AEST.
- •During AEDT, Sydney is 16 hours ahead of New York and 11 hours ahead of UTC.
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.
AEDT vs MST: Offsets, DST and Best Call Times
AEDT runs on Australian Eastern Daylight Time (AEDT) at UTC+11:00. MST runs on Mountain Standard Time (MST) at UTC-07:00. That puts AEDT 18 hours behind MST — a difference of -18h at the current offsets.
In practice, when it is 9:00 AM in AEDT it is 3:00 PM in MST on the previous day. Midnight in AEDT is 6:00 AM in MST. Neither zone observes daylight saving time, so the offset between them stays constant all year.
AEDT to MST time conversion table
| AEDT (AEDT) | MST (MST) | Day |
|---|---|---|
| 12:00 AM | 6:00 AM | previous day |
| 6:00 AM | 12:00 PM | previous day |
| 7:00 AM | 1:00 PM | previous day |
| 8:00 AM | 2:00 PM | previous day |
| 9:00 AM | 3:00 PM | previous day |
| 12:00 PM | 6:00 PM | previous day |
| 3:00 PM | 9:00 PM | previous day |
| 5:00 PM | 11:00 PM | previous day |
| 6:00 PM | 12:00 AM | same day |
| 9:00 PM | 3:00 AM | same day |
Why people convert AEDT to MST time
- Scheduling a call from AEDT to MST: a 10:00 AM start in AEDT lands at 4:00 PM in MST the previous day, so you can confirm the slot without doing the arithmetic yourself.
- Handling a -18h gap: AEDT and MST 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 MST is 3:00 PM in AEDT.
- Booking travel or deliveries: tracking MST local time against AEDT keeps pickup windows and arrival estimates honest across the -18h offset.
- Always state the zone abbreviation, not just the hour. "3:00 PM AEDT" is unambiguous; "3 PM" across a -18h gap is not.
- With a -18h gap there is no shared 9-to-5 window, so alternate the early start: one week AEDT takes the early slot, the next week MST does.
About AEDT (Australian Eastern Daylight Time)
Australian Eastern Daylight Time (AEDT) is the daylight saving period in south-eastern Australia, one hour ahead of Australian Eastern Standard Time (AEST, UTC+10:00). Because Australia is in the southern hemisphere, AEDT runs through the summer — from the first Sunday in October to the first Sunday in April — which is almost exactly the reverse of the European and North American schedules. New South Wales, Victoria, Tasmania and the Australian Capital Territory observe it; Queensland and the Northern Territory do not, so Brisbane stays on AEST year round while Sydney moves to AEDT. During AEDT, Sydney is 11 hours ahead of UTC and 16 hours ahead of New York.
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).
Best time to call between AEDT and MST
With a -18h offset there is no overlap inside a normal 9 AM – 5 PM day. MST opens at 9:00 AM MST, which is 3:00 PM in AEDT, so real-time calls need an early-morning or late-evening slot on one side.
Business hours overlap
AEDT and MST have no shared working hours because of the -18h gap. Teams need to alternate early starts or rely on asynchronous handovers.
AEDT is 18 hours behind MST (AEDT UTC+11:00 → MST UTC-07:00). 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
AEDT
❄ Currently in Standard Time
Standard: UTC+10:00 · DST: UTC+11:00
Clocks spring forward on Sat, Oct 3, 2026
MST
☀ Currently in DST
Standard: UTC-07:00 · DST: UTC-06:00
Clocks fall back on Sun, Nov 1, 2026
⚠ These locations are currently in different DST states, so the time difference may change when clocks adjust.
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 AEDT and MST?
AEDT (AEDT, UTC+11:00) is 18 hours behind MST (MST, UTC-07:00). The gap is currently -18h.
How do I convert AEDT time to MST time?
Add -18h to AEDT local time. For example, 9:00 AM in AEDT is 3:00 PM in MST (previous day).
What time is it in MST right now?
MST uses MST at UTC-07:00. Use the live converter at the top of this page — it updates in real time and already accounts for the -18h offset from AEDT.
What is the best time to call MST from AEDT?
There is no shared working-hours window because of the -18h gap. The closest option is 1:00 PM in AEDT, which is 7:00 PM in MST.
Which is behind, AEDT or MST?
AEDT is 18 hours behind MST. When it is 12:00 PM in AEDT it is 6:00 PM in MST.
Does daylight saving time affect the AEDT–MST difference?
Neither zone observes daylight saving time, so the -18h offset between AEDT and MST is fixed all year.
Which other cities share AEDT's time zone?
AEDT also covers Sydney, Melbourne, Canberra, Hobart, Newcastle.
Which countries use AEDT, AEDT's zone?
AEDT is used in Australia (NSW, Victoria, Tasmania, ACT).
Is there a day difference between AEDT and MST?
Sometimes. The -18h gap is large enough that 8:00 PM or later in AEDT already falls on the in MST.
What is the time difference between AEDT and MST?
MST is -18h from AEDT.
What timezone is AEDT in?
AEDT operates on its local timezone.
What timezone is MST in?
MST operates on its local timezone.
Which countries use AEDT (Australian Eastern Daylight Time)?
AEDT is used in Australia (NSW, Victoria, Tasmania, ACT).
Does AEDT observe daylight saving time?
Yes, AEDT switches to AEDT during summer months.
What are some interesting facts about AEDT?
AEDT runs from the first Sunday in October to the first Sunday in April. AEDT is one hour ahead of Australian Eastern Standard Time (AEST).
Which cities are in the MST timezone?
Major cities in the MST timezone include Denver, Phoenix, Salt Lake City, Calgary, Edmonton, Albuquerque, El Paso, Tucson.
What is the UTC offset for MST?
Mountain Standard Time (MST) is at UTC-07:00. During daylight saving time, it shifts to MDT.
What should I know about the MST timezone?
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.
When is it midnight in AEDT, what time is it in MST?
When it is 12:00 AM (midnight) in AEDT (AEDT), it is -18h later in MST (MST).
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See every conversion from AEDT →·See every conversion from MST →