HST to Vietnam
+17hHST
HSTSOURCEVietnam
ICTGreen rows indicate typical business hours (9 AM - 5 PM)
HST and ICT on the World Map
The map below highlights the HST (Hawaii Standard Time) and ICT (Indochina Time) timezone regions across the globe.
HST – Hawaii Standard Time
UTC-10:00Hawaii Standard Time (HST) is the time zone for the Hawaiian Islands, 10 hours behind UTC.
- •Hawaii does not observe daylight saving time.
- •HST is 5 hours behind EST in winter and 6 hours behind EDT in summer.
- •Hawaii is one of only two US states that don't observe DST (the other is Arizona).
ICT – Indochina Time
UTC+07:00Indochina Time (ICT) is the time zone for Vietnam, Thailand, Laos, and Cambodia, 7 hours ahead of UTC.
- •Bangkok is one of the most visited cities in the world.
- •ICT is 12 hours ahead of EST.
- •Thailand, Vietnam, and Cambodia all share ICT.
Comparing Time Zones: HST and Vietnam
HST runs on Hawaii Standard Time (HST) at UTC-10:00. Vietnam runs on Indochina Time (ICT) at UTC+07:00. That puts HST 17 hours ahead of Vietnam — a difference of +17h at the current offsets.
In practice, when it is 9:00 AM in HST it is 2:00 AM in Vietnam on the next day. Midnight in HST is 5:00 PM in Vietnam. Neither zone observes daylight saving time, so the offset between them stays constant all year.
HST to Vietnam time conversion table
| HST (HST) | Vietnam (ICT) | Day |
|---|---|---|
| 12:00 AM | 5:00 PM | same day |
| 6:00 AM | 11:00 PM | same day |
| 7:00 AM | 12:00 AM | next day |
| 8:00 AM | 1:00 AM | next day |
| 9:00 AM | 2:00 AM | next day |
| 12:00 PM | 5:00 AM | next day |
| 3:00 PM | 8:00 AM | next day |
| 5:00 PM | 10:00 AM | next day |
| 6:00 PM | 11:00 AM | next day |
| 9:00 PM | 2:00 PM | next day |
Why people convert HST to Vietnam time
- Scheduling a call from HST to Vietnam: a 10:00 AM start in HST lands at 3:00 AM in Vietnam the next day, so you can confirm the slot without doing the arithmetic yourself.
- Handling a +17h gap: HST and Vietnam 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 Vietnam is 2:00 AM in HST.
- Keeping family and friends in sync: knowing that 8:00 PM in HST is 1:00 PM in Vietnam makes it easy to avoid calling at 3 AM.
- Always state the zone abbreviation, not just the hour. "3:00 PM HST" is unambiguous; "3 PM" across a +17h gap is not.
- With a +17h gap there is no shared 9-to-5 window, so alternate the early start: one week HST takes the early slot, the next week Vietnam does.
About HST (Hawaii Standard Time)
Hawaii Standard Time (HST) is used in the state of Hawaii and does not observe daylight saving time. This makes HST one of the most consistent time zones in the US. The Hawaiian Islands are among the last places on Earth to see a new calendar day.
About ICT (Indochina Time)
Indochina Time (ICT) is used across Southeast Asia including Vietnam, Thailand, Laos, and Cambodia. Indonesia (Western time, WIB) also uses UTC+07:00. ICT does not observe daylight saving time.
Best time to call between HST and Vietnam
With a +17h offset there is no overlap inside a normal 9 AM – 5 PM day. Vietnam opens at 9:00 AM ICT, which is 2:00 AM in HST, so real-time calls need an early-morning or late-evening slot on one side.
Business hours overlap
HST and Vietnam have no shared working hours because of the +17h gap. Teams need to alternate early starts or rely on asynchronous handovers.
HST is 17 hours ahead of Vietnam (HST UTC-10:00 → ICT 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.
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 HST and Vietnam?
HST (HST, UTC-10:00) is 17 hours ahead of Vietnam (ICT, UTC+07:00). The gap is currently +17h.
How do I convert HST time to Vietnam time?
Add +17h to HST local time. For example, 9:00 AM in HST is 2:00 AM in Vietnam (next day).
What time is it in Vietnam right now?
Vietnam uses ICT at UTC+07:00. Use the live converter at the top of this page — it updates in real time and already accounts for the +17h offset from HST.
What is the best time to call Vietnam from HST?
There is no shared working-hours window because of the +17h gap. The closest option is 1:00 PM in HST, which is 6:00 AM in Vietnam.
Which is ahead, HST or Vietnam?
HST is 17 hours ahead of Vietnam. When it is 12:00 PM in HST it is 5:00 AM in Vietnam.
Do HST and Vietnam use different time zones?
HST uses HST at UTC-10:00, while Vietnam (Vietnam) uses ICT at UTC+07:00. The IANA identifiers are Pacific/Honolulu and Asia/Ho_Chi_Minh.
Does daylight saving time affect the HST–Vietnam difference?
Neither zone observes daylight saving time, so the +17h offset between HST and Vietnam is fixed all year.
Which other cities share HST's time zone?
HST also covers Honolulu, Hilo, Kailua, Pearl City, Kapolei.
Which countries use HST, HST's zone?
HST is used in United States (Hawaii).
Is there a day difference between HST and Vietnam?
Sometimes. The +17h gap is large enough that 8:00 PM or later in HST already falls on the next day in Vietnam.
What is the time difference between HST and Vietnam?
Vietnam is +17h from HST.
What timezone is HST in?
HST operates on its local timezone.
What timezone is Vietnam in?
Vietnam operates on its local timezone.
Which countries use HST (Hawaii Standard Time)?
HST is used in United States (Hawaii).
Does HST observe daylight saving time?
No, HST does not observe daylight saving time and remains at UTC-10:00 year-round.
What are some interesting facts about HST?
Hawaii does not observe daylight saving time. HST is 5 hours behind EST in winter and 6 hours behind EDT in summer.
Which cities are in the ICT timezone?
Major cities in the ICT timezone include Bangkok, Ho Chi Minh City, Hanoi, Jakarta, Phnom Penh, Vientiane.
What is the UTC offset for ICT?
Indochina Time (ICT) is at UTC+07:00.
What should I know about the ICT timezone?
Bangkok is one of the most visited cities in the world. ICT is 12 hours ahead of EST.
When is it midnight in HST, what time is it in Vietnam?
When it is 12:00 AM (midnight) in HST (HST), it is +17h later in Vietnam (ICT).
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