Does it account for Daylight Saving Time?

Yes, our converter uses the IANA timezone database, which includes all current DST rules for every timezone in the world.

UTC (Coordinated Universal Time) is the primary time standard by which the world regulates clocks. All timezones are defined as offsets from UTC.

Can I compare multiple timezones at once?

Yes, you can add multiple cities or timezones and see the equivalent times side by side.

How many timezones are there in the world?

There are 38 distinct UTC offsets in use, ranging from UTC-12 to UTC+14. This includes half-hour (UTC+5:30 India, UTC+9:30 Australia) and 45-minute offsets (UTC+5:45 Nepal, UTC+8:45 Australia).

What is the International Date Line?

The International Date Line (IDL) runs roughly along the 180° meridian in the Pacific Ocean. When you cross it westward, you gain a day; crossing eastward, you lose a day.

Why do some timezones have 30 or 45 minute offsets?

Countries chose offsets that best matched their solar noon. India uses UTC+5:30 and Nepal uses UTC+5:45 because standard hourly offsets didn't align well with their geography.

Which country has the most timezones?

France has the most (12 timezones) due to overseas territories. Russia spans 11 timezones. The US has 6 (including Hawaii and Alaska).

ICT to HST

-17h

ICT

ICTSOURCE

UTC+07:00

HH12

MM00

12:00 (24-hr)

12 AM6 AM12 PM6 PM12 AM

HST

UTC-10:00

HH07

MM00

(previous day)19:00 (24-hr)

12 AM6 AM12 PM6 PM12 AM

Quick Reference

Time Conversion Table

ICT

HST

12:00 AM

7:00 AM-1

2:00 AM

9:00 AM-1

4:00 AM

11:00 AM-1

6:00 AM

1:00 PM-1

8:00 AM

3:00 PM-1

10:00 AM

5:00 PM-1

12:00 PM

7:00 PM-1

2:00 PM

9:00 PM-1

4:00 PM

11:00 PM-1

6:00 PM

1:00 AM

8:00 PM

3:00 AM

10:00 PM

5:00 AM

Green rows indicate typical business hours (9 AM - 5 PM)

ICT and HST on the World Map

The map below highlights the ICT (Indochina Time) and HST (Hawaii Standard Time) timezone regions across the globe.

ICT Zone

→

HST Zone

Explore all world timezones interactively →

ICT – Indochina Time

UTC+07:00

Indochina Time (ICT) is the time zone for Vietnam, Thailand, Laos, and Cambodia, 7 hours ahead of UTC.

Countries in ICT

ThailandVietnamCambodiaLaosIndonesia (WIB)

Major Cities in ICT

BangkokHo Chi Minh CityHanoiJakartaPhnom PenhVientiane

Key Facts about ICT

•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.

Daylight Saving:No – UTC+07:00 year-round

Learn more about ICT on Wikipedia

HST – Hawaii Standard Time

UTC-10:00

Hawaii Standard Time (HST) is the time zone for the Hawaiian Islands, 10 hours behind UTC.

Countries in HST

United States (Hawaii)

Major Cities in HST

HonoluluHiloKailuaPearl CityKapolei

Key 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.
•Hawaii is one of only two US states that don't observe DST (the other is Arizona).

Daylight Saving:No – UTC-10:00 year-round

Learn more about HST on Wikipedia

ICT to HST Time Difference – Complete Guide

ICT runs on Indochina Time (ICT) at UTC+07:00. HST runs on Hawaii Standard Time (HST) at UTC-10:00. That puts ICT 17 hours behind HST — a difference of -17h at the current offsets.

In practice, when it is 9:00 AM in ICT it is 4:00 PM in HST on the previous day. Midnight in ICT is 7:00 AM in HST. Neither zone observes daylight saving time, so the offset between them stays constant all year.

ICT to HST time conversion table

ICT (ICT)	HST (HST)	Day
12:00 AM	7:00 AM	previous day
6:00 AM	1:00 PM	previous day
7:00 AM	2:00 PM	previous day
8:00 AM	3:00 PM	previous day
9:00 AM	4:00 PM	previous day
12:00 PM	7:00 PM	previous day
3:00 PM	10:00 PM	previous day
5:00 PM	12:00 AM	same day
6:00 PM	1:00 AM	same day
9:00 PM	4:00 AM	same day

Why people convert ICT to HST time

Scheduling a call from ICT to HST: a 10:00 AM start in ICT lands at 5:00 PM in HST the previous day, so you can confirm the slot without doing the arithmetic yourself.
Handling a -17h gap: ICT and HST 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 HST is 4:00 PM in ICT.
Watching a live event or market open: ICT viewers need 4:00 PM in HST to catch a 9:00 AM start there, and 5:00 PM if the event is anchored to ICT.

Always state the zone abbreviation, not just the hour. "3:00 PM ICT" 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 ICT takes the early slot, the next week HST does.

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.

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.

Best time to call between ICT and HST

With a -17h offset there is no overlap inside a normal 9 AM – 5 PM day. HST opens at 9:00 AM HST, which is 4:00 PM in ICT, so real-time calls need an early-morning or late-evening slot on one side.

Business hours overlap

ICT and HST have no shared working hours because of the -17h gap. Teams need to alternate early starts or rely on asynchronous handovers.

ICT is 17 hours behind HST (ICT UTC+07:00 → HST UTC-10:00). 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:

⏳

History of Timekeeping

From sundials to atomic clocks - 5000 years of measuring time

🌍

How Time Zones Work

UTC, offsets, and why zones don't follow straight lines

☀️

Daylight Saving Time

DST dates, which countries observe it, and the ongoing debate

Frequently Asked Questions

What is the time difference between ICT and HST?

ICT (ICT, UTC+07:00) is 17 hours behind HST (HST, UTC-10:00). The gap is currently -17h.

How do I convert ICT time to HST time?

Add -17h to ICT local time. For example, 9:00 AM in ICT is 4:00 PM in HST (previous day).

What time is it in HST right now?

HST uses HST at UTC-10:00. Use the live converter at the top of this page — it updates in real time and already accounts for the -17h offset from ICT.