MST to SST Converter
Convert time between Mountain Standard Time (MST) and Samoa Standard Time (SST)
Mountain Standard Time (MST)
Samoa Standard Time (SST)
Time Difference
Samoa Standard Time (SST) is 0 hours ahead of Mountain Standard Time (MST)
Select Date
Select Time
Quick Reference
| MST | SST |
|---|---|
| 20:00 | 15:00 |
| 22:00 | 17:00 |
| 00:00 | 19:00 |
| 02:00 | 21:00 |
| 04:00 | 23:00 |
| 06:00 | 01:00 |
| 08:00 | 03:00 |
| 10:00 | 05:00 |
| 12:00 | 07:00 |
| 14:00 | 09:00 |
| 16:00 | 11:00 |
| 18:00 | 13:00 |
Top 10 Most Common Time Zones
| Abbreviation | Full Name | UTC Offset | Typical Use |
|---|---|---|---|
| UTC | Coordinated Universal Time | UTC ±0 | Global reference standard (servers, logs, APIs) |
| EST / EDT | Eastern (US) Time | UTC −5 / −4 | New York, Toronto — North American business hub |
| CST / CDT | Central (US) Time | UTC −6 / −5 | Chicago, Dallas — US central business region |
| PST / PDT | Pacific (US) Time | UTC −8 / −7 | San Francisco, Los Angeles — tech industry standard |
| GMT / BST | Greenwich Mean / British Summer Time | UTC 0 / +1 | UK, used globally as a reference with UTC |
| CET / CEST | Central European (Summer) Time | UTC +1 / +2 | Paris, Berlin, Amsterdam — EU business core |
| IST | India Standard Time | UTC +5:30 | India — major IT & outsourcing region |
| CST | China Standard Time | UTC +8 | Beijing, Shanghai — East Asia business hub |
| JST | Japan Standard Time | UTC +9 | Tokyo — finance & tech hub |
| AEST / AEDT | Australian Eastern (Daylight) Time | UTC +10 / +11 | Sydney, Melbourne — APAC regional business |
Why Time Zone Abbreviations Are Ambiguous
Unlike standardized identifiers (like America/New_York or Europe/London from the IANA tz database), abbreviations such as "CST" or "IST" are not globally unique. They can refer to different time zones depending on context — country, region, or even time of year (due to daylight saving time).
Common Ambiguous Time Zone Abbreviations
| Abbrev. | Common Meaning(s) | UTC Offset | Region(s) |
|---|---|---|---|
| CST | Central Standard Time / China Standard Time / Cuba Standard Time | UTC−6 / UTC+8 / UTC−5 | North America, China, Cuba |
| IST | Indian Standard Time / Irish Standard Time / Israel Standard Time | UTC+5:30 / UTC+1 / UTC+2 | India, Ireland, Israel |
| AST | Atlantic Standard Time / Arabia Standard Time | UTC−4 / UTC+3 | Caribbean, Canada, Middle East |
| PST | Pacific Standard Time / Philippine Standard Time | UTC−8 / UTC+8 | North America, Philippines |
| EST | Eastern Standard Time (North America / Australia) | UTC−5 / UTC+10 | North America, Australia |
✅ Best Practice
To avoid ambiguity, always:
- Use IANA tz identifiers — e.g.,
America/New_Yorkinstead of "EST" - Specify UTC offset explicitly — e.g.,
UTC−5when abbreviations must be used - Include the full timezone name — e.g., "Eastern Standard Time (EST)" with UTC offset
About MST to SST Time Conversion
Converting time between Mountain Standard Time (MST) and Samoa Standard Time (SST) bridges the US Mountain region and the South Pacific. MST is UTC-7, while SST is UTC-11 and stays constant year-round (American Samoa does not observe daylight saving time). That makes SST 4 hours behind MST during the US winter — from the first Sunday in November to the second Sunday in March. From mid-March to early November the Mountain region (excluding Arizona) shifts to MDT (UTC-6) and the gap widens to 5 hours. Most of Arizona stays on MST year-round.
This converter uses the IANA timezone database (America/Denver) to handle DST transitions automatically. Whether you're booking a call between Denver, Salt Lake City, or Phoenix and Pago Pago, or coordinating with Pacific-based teams from Mountain time offices, the tool removes the manual offset arithmetic.
Common Use Cases for MST to SST Conversion
Business & Work
- Scheduling video calls between Denver, Salt Lake City, or Phoenix and American Samoa
- Coordinating US Mountain–Pacific remote team handoffs
- Planning conference calls that bridge Mountain and Samoan working hours
Personal & Travel
- Calling family in American Samoa from the Mountain US states
- Planning flight connections via Los Angeles or Honolulu from Denver or Phoenix
- Coordinating watch parties for live NBA, NHL, or other US sports during the American winter
Time Zone Information
Mountain Standard Time (MST)
- UTC Offset: UTC-7 (UTC-6 during MDT)
- IANA Timezone: America/Denver
- Daylight Saving: MST applies in winter; switches to MDT (UTC-6) mid-March to early November. Most of Arizona stays on MST year-round.
- Major Cities: Denver, Phoenix, Salt Lake City, Albuquerque, Boise
- Coverage: US Mountain time zone in winter, plus most of Arizona year-round
Samoa Standard Time (SST)
- UTC Offset: UTC-11
- IANA Timezone: Pacific/Pago_Pago
- Daylight Saving: None - American Samoa does not observe daylight saving time
- Major Cities: Pago Pago, Tafuna, Nu'uuli, Faleniu, Aua
- Coverage: American Samoa and Midway Atoll
Quick Reference: MST to SST
Remember: SST is 4 hours behind MST. From mid-March to early November the Mountain region shifts to MDT (UTC-6) and the gap becomes 5 hours. Most of Arizona stays on MST year-round.
Frequently Asked Questions
What is the time difference between MST and SST?
Mountain Standard Time (MST) is UTC-7, while Samoa Standard Time (SST) is UTC-11. SST is 4 hours behind MST. When it is 12:00 PM in Denver or Phoenix, it is 8:00 AM in Pago Pago.
When does this MST to SST conversion apply?
It applies during US winter, from the first Sunday in November to the second Sunday in March. From mid-March to early November the Mountain region (excluding Arizona) shifts to MDT (UTC-6) and the gap widens to 5 hours. Most of Arizona stays on MST year-round. American Samoa stays on SST (UTC-11) year-round.
How does the time difference change throughout the year?
The gap is 4 hours during MST (early November to mid-March, plus Arizona year-round) and 5 hours during MDT (mid-March to early November). American Samoa never observes daylight saving, so any seasonal change comes from the US side.
What are the best times for MST–SST business calls?
A 4-hour gap leaves a comfortable afternoon overlap: 1:00 PM MST is 9:00 AM SST. Late-morning Pago Pago and early-afternoon Denver is the most usable live-call window.
Which countries and regions use SST?
Samoa Standard Time (UTC-11) is used in American Samoa and the uninhabited Midway Atoll. The independent state of Samoa is on UTC+13, on the opposite side of the international date line. Major American Samoa locations include Pago Pago, Tafuna, and Nu’uuli.
Which countries and regions use MST?
Mountain Standard Time covers the US Mountain time zone in winter — Colorado, Wyoming, Montana, Utah, New Mexico, and parts of neighboring states. Most of Arizona stays on MST year-round. Major cities include Denver, Phoenix, Salt Lake City, Albuquerque, and Boise.
Pro Tips
- • SST is 4 hours behind MST — both sides share the same calendar day.
- • American Samoa never observes daylight saving, so any seasonal shift comes from the US side switching between MST and MDT.
- • Most of Arizona stays on MST year-round — when you mean Phoenix, the gap is always 4 hours regardless of season.
- • Early afternoon MST and morning SST is the most workable overlap window for live calls.
- • During US daylight saving (mid-March to early November) the Mountain region shifts to MDT (UTC-6) and the gap becomes 5 hours.
- • For one-off calls, double-check the IANA zones (America/Denver or America/Phoenix, Pacific/Pago_Pago) in your calendar tool.