AEDT to MST Time Converter
MST is 17 hours behind AEDT. AEDT is UTC+11:00, and The US Mountain states are currently on MDT (UTC-6:00).
Best Time to Call Between AEDT and MST
Both zones are inside normal business hours between 9:00 AM and 10:00 AM AEDT — that's 4:00 PM to 5:00 PM MST. That's a 1-hour window.
both at work AEDT only MST only neither — hours along the strip are AEDT.
Common Times Converted
AEDT on the left, MST on the right.
AEDT to MST: Full 24-Hour Conversion Table
Shaded rows are working hours; the darker shade marks the hours when both zones are at work.
| AEDT | MST | Working hours |
|---|---|---|
| 12:00 AM | 7:00 AM prev day | — |
| 1:00 AM | 8:00 AM prev day | — |
| 2:00 AM | 9:00 AM prev day | MST only |
| 3:00 AM | 10:00 AM prev day | MST only |
| 4:00 AM | 11:00 AM prev day | MST only |
| 5:00 AM | 12:00 PM prev day | MST only |
| 6:00 AM | 1:00 PM prev day | MST only |
| 7:00 AM | 2:00 PM prev day | MST only |
| 8:00 AM | 3:00 PM prev day | MST only |
| 9:00 AM | 4:00 PM prev day | Both zones |
| 10:00 AM | 5:00 PM prev day | AEDT only |
| 11:00 AM | 6:00 PM prev day | AEDT only |
| 12:00 PM | 7:00 PM prev day | AEDT only |
| 1:00 PM | 8:00 PM prev day | AEDT only |
| 2:00 PM | 9:00 PM prev day | AEDT only |
| 3:00 PM | 10:00 PM prev day | AEDT only |
| 4:00 PM | 11:00 PM prev day | AEDT only |
| 5:00 PM | 12:00 AM | — |
| 6:00 PM | 1:00 AM | — |
| 7:00 PM | 2:00 AM | — |
| 8:00 PM | 3:00 AM | — |
| 9:00 PM | 4:00 AM | — |
| 10:00 PM | 5:00 AM | — |
| 11:00 PM | 6:00 AM | — |
What AEDT and MST Actually Are
AEDT — Australian Eastern Daylight Time
Sydney, Melbourne, Canberra, Hobart from October to April. Standing at UTC+11:00 as written, and the region does change its clocks, so its live offset moves by an hour twice a year. The next change is on Sunday, April 4, 2027, to AEST. Brisbane and the rest of Queensland stay on AEST year-round, so they fall an hour behind Sydney each summer.
AEDT is the southern summer half of Eastern Australia, running roughly October to April — the opposite half of the year from northern hemisphere daylight time.
MST — Mountain Standard Time
Denver, Salt Lake City, Calgary — and Phoenix year-round. Standing at UTC-7:00 as written, and the region does change its clocks, so its live offset moves by an hour twice a year. The next change is on Sunday, November 1, 2026, to MST. Arizona stays on MST all year, so Phoenix and Denver are an hour apart for eight months and identical for four.
Arizona has stayed on MST year-round since 1968 — the Navajo Nation within it does observe daylight saving, making the state a patchwork.
What This Means in Practice
The date changes mid-working-day
For 8 of the eight hours in a normal AEDT working day, the equivalent MST time falls on a different calendar date. Anything scheduled in that stretch needs the date checked as well as the time, or a Tuesday call quietly becomes a Wednesday one at the other end.
Both sides change clocks, on different dates
Both regions observe daylight saving but do not switch on the same day, so for a week or two each spring and fall the gap between them is an hour different from the rest of the year. Those short windows are where recurring invitations quietly break.
Nearly opposite sides of the clock
At 17 hours apart, one side's morning is the other side's night. Handing work over at the end of a shift usually beats trying to get both parties in the same call.
Major Cities in Each Zone
Cities on AEDT
Cities on MST
Frequently Asked Questions
What is the time difference between AEDT and MST?
MST is 17 hours behind AEDT. That is the live figure. Taken strictly as written, the gap between AEDT and MST is 18 hours — the two differ because at least one of these regions is currently on daylight saving.
What is 9:00 AM AEDT in MST?
9:00 AM AEDT is 4:00 PM the previous day MST.
What are the best hours to schedule a call between AEDT and MST?
Between 9:00 AM and 10:00 AM AEDT, which is 4:00 PM to 5:00 PM MST. Both sides are inside normal business hours through that window.
Does the difference between AEDT and MST change during the year?
Yes. Both regions observe daylight saving, and they do not switch on the same dates, so the gap shifts by an hour at least twice a year. The next clock change is on Sunday, April 4, 2027.
Does AEDT always mean Australian Eastern Daylight Time?
Brisbane and the rest of Queensland stay on AEST year-round, so they fall an hour behind Sydney each summer.
Does MST always mean Mountain Standard Time?
Arizona stays on MST all year, so Phoenix and Denver are an hour apart for eight months and identical for four.