HST to ICT
+17hHST
HSTSOURCEICT
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 ICT
HST runs on Hawaii Standard Time (HST) at UTC-10:00. ICT runs on Indochina Time (ICT) at UTC+07:00. That puts HST 17 hours ahead of ICT — a difference of +17h at the current offsets.
In practice, when it is 9:00 AM in HST it is 2:00 AM in ICT on the next day. Midnight in HST is 5:00 PM in ICT. Neither zone observes daylight saving time, so the offset between them stays constant all year.
HST to ICT time conversion table
| HST (HST) | ICT (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 ICT time
- Scheduling a call from HST to ICT: a 10:00 AM start in HST lands at 3:00 AM in ICT the next day, so you can confirm the slot without doing the arithmetic yourself.
- Handling a +17h gap: HST and ICT 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 ICT is 2:00 AM in HST.
- Keeping family and friends in sync: knowing that 8:00 PM in HST is 1:00 PM in ICT 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 ICT 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 ICT
With a +17h offset there is no overlap inside a normal 9 AM – 5 PM day. ICT 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 ICT 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 ICT (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 ICT?
HST (HST, UTC-10:00) is 17 hours ahead of ICT (ICT, UTC+07:00). The gap is currently +17h.
How do I convert HST time to ICT time?
Add +17h to HST local time. For example, 9:00 AM in HST is 2:00 AM in ICT (next day).
What time is it in ICT right now?
ICT 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 ICT 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 ICT.
Which is ahead, HST or ICT?
HST is 17 hours ahead of ICT. When it is 12:00 PM in HST it is 5:00 AM in ICT.
Does daylight saving time affect the HST–ICT difference?
Neither zone observes daylight saving time, so the +17h offset between HST and ICT 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 ICT?
Sometimes. The +17h gap is large enough that 8:00 PM or later in HST already falls on the next day in ICT.
What is the time difference between HST and ICT?
ICT is +17h from HST.
What timezone is HST in?
HST operates on its local timezone.
What timezone is ICT in?
ICT 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 ICT?
When it is 12:00 AM (midnight) in HST (HST), it is +17h later in ICT (ICT).
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See every conversion from HST →·See every conversion from ICT →