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).

BST to HST

-11h

BST

BSTSOURCE

UTC+01:00☀ DST active

HH12

MM00

12:00 (24-hr)

12 AM6 AM12 PM6 PM12 AM

HST

UTC-10:00

HH01

MM00

01:00 (24-hr)

12 AM6 AM12 PM6 PM12 AM

Quick Reference

Time Conversion Table

BST

HST

12:00 AM

1:00 PM-1

2:00 AM

3:00 PM-1

4:00 AM

5:00 PM-1

6:00 AM

7:00 PM-1

8:00 AM

9:00 PM-1

10:00 AM

11:00 PM-1

12:00 PM

1:00 AM

2:00 PM

3:00 AM

4:00 PM

5:00 AM

6:00 PM

7:00 AM

8:00 PM

9:00 AM

10:00 PM

11:00 AM

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

BST and HST on the World Map

The map below highlights the BST (British Summer Time) and HST (Hawaii Standard Time) timezone regions across the globe.

BST Zone

→

HST Zone

Explore all world timezones interactively →

BST – British Summer Time

UTC+01:00

British Summer Time (BST, UTC+01:00) is the daylight saving period in the United Kingdom, running from late March to late October.

Countries in BST

United Kingdom

Major Cities in BST

LondonBirminghamManchesterGlasgowEdinburghCardiffBelfastLiverpoolBristolLeeds

Key Facts about BST

•BST runs from the last Sunday in March to the last Sunday in October.
•BST is exactly one hour ahead of GMT, the UK's standard time.
•During BST, London is 4 hours ahead of New York while the US is on Eastern Daylight Time.
•The Isle of Man and the Channel Islands also observe BST.

Daylight Saving:Yes – switches to BST

Learn more about BST 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

BST vs HST: Offsets, DST and Best Call Times

BST runs on British Summer Time (BST) at UTC+01:00. HST runs on Hawaii Standard Time (HST) at UTC-10:00. That puts BST 11 hours behind HST — a difference of -11h at the current offsets.

In practice, when it is 9:00 AM in BST it is 10:00 PM in HST on the previous day. Midnight in BST is 1:00 PM in HST. Neither zone observes daylight saving time, so the offset between them stays constant all year.

BST to HST time conversion table

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

Why people convert BST to HST time

Scheduling a call from BST to HST: a 10:00 AM start in BST lands at 11:00 PM in HST the previous day, so you can confirm the slot without doing the arithmetic yourself.
Handling a -11h gap: BST 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 10:00 PM in BST.
Coordinating a BST-based team with HST contacts: quoting times in the other side's local clock — not your own — removes the single biggest source of missed meetings.

Always state the zone abbreviation, not just the hour. "3:00 PM BST" is unambiguous; "3 PM" across a -11h gap is not.
With a -11h gap there is no shared 9-to-5 window, so alternate the early start: one week BST takes the early slot, the next week HST does.

About BST (British Summer Time)

British Summer Time (BST) is the daylight saving period in the United Kingdom, when clocks move one hour forward from Greenwich Mean Time (GMT, UTC+00:00) to UTC+01:00. It runs from the last Sunday in March to the last Sunday in October. England, Scotland, Wales and Northern Ireland all follow it, along with the Isle of Man and the Channel Islands of Jersey and Guernsey. During BST, London is one hour ahead of UTC, four hours ahead of New York on Eastern Daylight Time, and five hours ahead of New York once the United States returns to Eastern Standard Time in November. BST is also used to abbreviate Bangladesh Standard Time (UTC+06:00), which is listed separately on this site.

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 BST and HST

With a -11h offset there is no overlap inside a normal 9 AM – 5 PM day. HST opens at 9:00 AM HST, which is 10:00 PM in BST, so real-time calls need an early-morning or late-evening slot on one side.

Business hours overlap

BST and HST have no shared working hours because of the -11h gap. Teams need to alternate early starts or rely on asynchronous handovers.

BST is 11 hours behind HST (BST UTC+01:00 → 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.

🕐 Daylight Saving Time Info

BST

☀ Currently in DST

Standard: UTC+00:00 · DST: UTC+01:00

Clocks fall back on Sun, Oct 25, 2026

HST

Does not observe DST

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 BST and HST?

BST (BST, UTC+01:00) is 11 hours behind HST (HST, UTC-10:00). The gap is currently -11h.

How do I convert BST time to HST time?

Add -11h to BST local time. For example, 9:00 AM in BST is 10:00 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 -11h offset from BST.