IST to MST Time Converter
MST is 11 hours and 30 minutes behind IST. IST is UTC+5:30, and The US Mountain states are currently on MDT (UTC-6:00).
Best Time to Call Between IST and MST
Standard 9-to-5 hours in these two zones never overlap, so someone has to take the call outside their working day. The most workable window is 7:00 AM to 10:00 AM IST, which is 7:30 PM to 10:30 PM MST.
both at work IST only MST only neither — hours along the strip are IST.
Common Times Converted
IST on the left, MST on the right.
IST to MST: Full 24-Hour Conversion Table
Shaded rows are working hours; the darker shade marks the hours when both zones are at work.
| IST | MST | Working hours |
|---|---|---|
| 12:00 AM | 12:30 PM prev day | MST only |
| 1:00 AM | 1:30 PM prev day | MST only |
| 2:00 AM | 2:30 PM prev day | MST only |
| 3:00 AM | 3:30 PM prev day | MST only |
| 4:00 AM | 4:30 PM prev day | MST only |
| 5:00 AM | 5:30 PM prev day | — |
| 6:00 AM | 6:30 PM prev day | — |
| 7:00 AM | 7:30 PM prev day | — |
| 8:00 AM | 8:30 PM prev day | — |
| 9:00 AM | 9:30 PM prev day | IST only |
| 10:00 AM | 10:30 PM prev day | IST only |
| 11:00 AM | 11:30 PM prev day | IST only |
| 12:00 PM | 12:30 AM | IST only |
| 1:00 PM | 1:30 AM | IST only |
| 2:00 PM | 2:30 AM | IST only |
| 3:00 PM | 3:30 AM | IST only |
| 4:00 PM | 4:30 AM | IST only |
| 5:00 PM | 5:30 AM | — |
| 6:00 PM | 6:30 AM | — |
| 7:00 PM | 7:30 AM | — |
| 8:00 PM | 8:30 AM | — |
| 9:00 PM | 9:30 AM | MST only |
| 10:00 PM | 10:30 AM | MST only |
| 11:00 PM | 11:30 AM | MST only |
What IST and MST Actually Are
IST — India Standard Time
Mumbai, Delhi, Bengaluru, Chennai, Kolkata, Hyderabad — and Colombo. Standing at UTC+5:30 as written, and the region does not change its clocks, so that offset holds all year. IST also stands for Irish Standard Time (UTC+1) and Israel Standard Time (UTC+2). This page covers the Indian one, which is by far the most searched.
India runs a single time zone across a country wide enough for two, which is why sunrise in the north-east can come nearly two hours before Mumbai's. Proposals for a second zone resurface regularly and have never been adopted.
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
Expect times on the half hour
IST sits on a 30-minute offset rather than a whole hour, so a round number on one side is never a round number on the other. A 9:00 meeting becomes 30 minutes past the hour, which is exactly the detail calendar invitations get wrong when someone converts in their head.
The date changes mid-working-day
For 3 of the eight hours in a normal IST 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.
This gap is not fixed
MST changes its clocks and IST does not, so the difference between them moves by an hour twice a year. A recurring meeting set now will drift for one side from Sunday, November 1, 2026 unless someone resets it.
Nearly opposite sides of the clock
At 11 hours and 30 minutes 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 IST
Cities on MST
Frequently Asked Questions
What is the time difference between IST and MST?
MST is 11 hours and 30 minutes behind IST. That is the live figure. Taken strictly as written, the gap between IST and MST is 12 hours and 30 minutes — the two differ because at least one of these regions is currently on daylight saving.
What is 9:00 AM IST in MST?
9:00 AM IST is 9:30 PM the previous day MST.
What are the best hours to schedule a call between IST and MST?
Standard business hours in these two zones do not overlap at all, so one side has to work outside the 9-to-5. The most workable window is 7:00 AM to 10:00 AM IST, which is 7:30 PM to 10:30 PM MST.
Does the difference between IST and MST change during the year?
Yes. MST observes daylight saving and IST does not, so the gap shifts by an hour at least twice a year. The next clock change is on Sunday, November 1, 2026.
Does IST always mean India Standard Time?
IST also stands for Irish Standard Time (UTC+1) and Israel Standard Time (UTC+2). This page covers the Indian one, which is by far the most searched.
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.