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).

Sri Lanka to HST

-15h 30m

Sri Lanka

ISTSOURCE

UTC+05:30

HH12

MM00

12:00 (24-hr)

12 AM6 AM12 PM6 PM12 AM

HST

UTC-10:00

HH08

MM30

(previous day)20:30 (24-hr)

12 AM6 AM12 PM6 PM12 AM

Quick Reference

Time Conversion Table

Sri Lanka

HST

12:00 AM

8:30 AM-1

2:00 AM

10:30 AM-1

4:00 AM

12:30 PM-1

6:00 AM

2:30 PM-1

8:00 AM

4:30 PM-1

10:00 AM

6:30 PM-1

12:00 PM

8:30 PM-1

2:00 PM

10:30 PM-1

4:00 PM

12:30 AM

6:00 PM

2:30 AM

8:00 PM

4:30 AM

10:00 PM

6:30 AM

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

IST and HST on the World Map

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

IST Zone

→

HST Zone

Explore all world timezones interactively →

IST – India Standard Time

UTC+05:30

India Standard Time (IST) is the time zone for India and Sri Lanka, 5 hours and 30 minutes ahead of UTC.

Countries in IST

IndiaSri Lanka

Major Cities in IST

MumbaiDelhiBangaloreKolkataChennaiHyderabadPuneAhmedabadColomboJaipurLucknowSurat

Key Facts about IST

•India is 10 hours 30 minutes ahead of EST and 5 hours 30 minutes ahead of GMT.
•India uses a single time zone despite spanning 30° of longitude.
•IST is one of only a handful of time zones with a 30-minute offset.
•IST is the most populous single time zone in the world with over 1.4 billion people.
•The Bombay Stock Exchange (BSE) and National Stock Exchange (NSE) operate on IST.

Daylight Saving:No – UTC+05:30 year-round

Learn more about IST 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

Sri Lanka to HST Time Difference – Complete Guide

Sri Lanka runs on India Standard Time (IST) at UTC+05:30. HST runs on Hawaii Standard Time (HST) at UTC-10:00. That puts Sri Lanka 15 hours 30 minutes behind HST — a difference of -15h 30m at the current offsets.

In practice, when it is 9:00 AM in Sri Lanka it is 5:30 PM in HST on the previous day. Midnight in Sri Lanka is 8:30 AM in HST. Neither zone observes daylight saving time, so the offset between them stays constant all year.

Sri Lanka to HST time conversion table

Sri Lanka (IST)	HST (HST)	Day
12:00 AM	8:30 AM	previous day
6:00 AM	2:30 PM	previous day
7:00 AM	3:30 PM	previous day
8:00 AM	4:30 PM	previous day
9:00 AM	5:30 PM	previous day
12:00 PM	8:30 PM	previous day
3:00 PM	11:30 PM	previous day
5:00 PM	1:30 AM	same day
6:00 PM	2:30 AM	same day
9:00 PM	5:30 AM	same day

Why people convert Sri Lanka to HST time

Scheduling a call from Sri Lanka to HST: a 10:00 AM start in Sri Lanka lands at 6:30 PM in HST the previous day, so you can confirm the slot without doing the arithmetic yourself.
Handling a -15h 30m gap: Sri Lanka 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 5:30 PM in Sri Lanka.
Booking travel or deliveries: tracking HST local time against Sri Lanka keeps pickup windows and arrival estimates honest across the -15h 30m offset.

Always state the zone abbreviation, not just the hour. "3:00 PM IST" is unambiguous; "3 PM" across a -15h 30m gap is not.
With a -15h 30m gap there is no shared 9-to-5 window, so alternate the early start: one week Sri Lanka takes the early slot, the next week HST does.

About IST (India Standard Time)

India Standard Time (IST) is the time observed throughout India and Sri Lanka. It is based on the 82.5°E meridian, passing through Mirzapur in Uttar Pradesh. India uses a single time zone despite spanning roughly 30° of longitude, which has been debated. IST does not observe daylight saving time. India is the world's most populous country, making IST one of the most-used time zones globally. The IT outsourcing industry and call centers operate primarily on IST, making the EST-to-IST conversion one of the most searched timezone conversions.

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 Sri Lanka and HST

With a -15h 30m offset there is no overlap inside a normal 9 AM – 5 PM day. HST opens at 9:00 AM HST, which is 5:30 PM in Sri Lanka, so real-time calls need an early-morning or late-evening slot on one side.

Business hours overlap

Sri Lanka and HST have no shared working hours because of the -15h 30m gap. Teams need to alternate early starts or rely on asynchronous handovers.

Sri Lanka is 15 hours 30 minutes behind HST (IST UTC+05:30 → 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 Sri Lanka and HST?

Sri Lanka (IST, UTC+05:30) is 15 hours 30 minutes behind HST (HST, UTC-10:00). The gap is currently -15h 30m.

How do I convert Sri Lanka time to HST time?

Add -15h 30m to Sri Lanka local time. For example, 9:00 AM in Sri Lanka is 5:30 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 -15h 30m offset from Sri Lanka.