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).

Mumbai to BST

-4h 30m

Mumbai

ISTSOURCE

India · UTC+05:30

HH12

MM00

12:00 (24-hr)

12 AM6 AM12 PM6 PM12 AM

BST

UTC+01:00☀ DST active

HH07

MM30

07:30 (24-hr)

12 AM6 AM12 PM6 PM12 AM

Quick Reference

Time Conversion Table

Mumbai

BST

12:00 AM

7:30 PM-1

2:00 AM

9:30 PM-1

4:00 AM

11:30 PM-1

6:00 AM

1:30 AM

8:00 AM

3:30 AM

10:00 AM

5:30 AM

12:00 PM

7:30 AM

2:00 PM

9:30 AM

4:00 PM

11:30 AM

6:00 PM

1:30 PM

8:00 PM

3:30 PM

10:00 PM

5:30 PM

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

IST and BST on the World Map

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

IST Zone

→

BST 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

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

About Mumbai

Wikipedia

Mumbai operates on India Standard Time (IST), UTC+5:30. As India's financial capital and home to BSE (Asia's oldest stock exchange), Mumbai timing is crucial for Asia markets.

Population:12.4 million

Metro:21.3 million

Business Hours:9:30 AM - 5:30 PM IST

Currency:INR (₹)

Stock Exchange:BSE (Bombay Stock Exchange), NSE

Key Landmarks

Gateway of IndiaChhatrapati Shivaji TerminusMarine DriveElephanta CavesHaji Ali Dargah

Did You Know?

The Mumbai local trains carry over 7.5 million passengers daily.

Learn more about IST timezone →

Mumbai vs BST: Offsets, DST and Best Call Times

Mumbai runs on India Standard Time (IST) at UTC+05:30. BST runs on British Summer Time (BST) at UTC+01:00. That puts Mumbai 4 hours 30 minutes behind BST — a difference of -4h 30m at the current offsets.

In practice, when it is 9:00 AM in Mumbai it is 4:30 AM in BST. Midnight in Mumbai is 7:30 PM in BST. Neither zone observes daylight saving time, so the offset between them stays constant all year.

Mumbai to BST time conversion table

Mumbai (IST)	BST (BST)	Day
12:00 AM	7:30 PM	previous day
6:00 AM	1:30 AM	same day
7:00 AM	2:30 AM	same day
8:00 AM	3:30 AM	same day
9:00 AM	4:30 AM	same day
12:00 PM	7:30 AM	same day
3:00 PM	10:30 AM	same day
5:00 PM	12:30 PM	same day
6:00 PM	1:30 PM	same day
9:00 PM	4:30 PM	same day

Why people convert Mumbai to BST time

Scheduling a call from Mumbai to BST: a 10:00 AM start in Mumbai lands at 5:30 AM in BST, so you can confirm the slot without doing the arithmetic yourself.
Finding shared working hours: both Mumbai and BST are inside the 9-to-5 working day between 1:30 PM and 5:00 PM IST time (9:00 AM–12:30 PM BST). That is roughly 3 hours 30 minutes of usable overlap.
Keeping family and friends in sync: knowing that 8:00 PM in Mumbai is 3:30 PM in BST makes it easy to avoid calling at 3 AM.

Always state the zone abbreviation, not just the hour. "3:00 PM IST" is unambiguous; "3 PM" across a -4h 30m gap is not.
Block 1:30 PM–5:00 PM IST as the recurring meeting window if you work primarily from Mumbai and need BST colleagues present.

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 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.

Best time to call between Mumbai and BST

Both Mumbai and BST sit inside the 9 AM – 5 PM working day between 1:30 PM–5:00 PM IST, which is 9:00 AM–12:30 PM BST. That gives roughly 3 hours and 30 minutes of shared time — the safest window for a live call or meeting.

Business hours overlap

Mumbai and BST overlap for about 3 hours during the working day — enough for meetings if you avoid the edges of the window.

Mumbai is 4 hours 30 minutes behind BST (IST UTC+05:30 → BST UTC+01:00). The shared working window is 1:30 PM–5:00 PM IST. Remember to re-check around daylight-saving transitions.

🕐 Daylight Saving Time Info

Mumbai

Does not observe DST

BST

☀ Currently in DST

Standard: UTC+00:00 · DST: UTC+01:00

Clocks fall back on Sun, Oct 25, 2026

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 Mumbai and BST?

Mumbai (IST, UTC+05:30) is 4 hours 30 minutes behind BST (BST, UTC+01:00). The gap is currently -4h 30m.

How do I convert Mumbai time to BST time?

Add -4h 30m to Mumbai local time. For example, 9:00 AM in Mumbai is 4:30 AM in BST.

What time is it in BST right now?

BST uses BST at UTC+01:00. Use the live converter at the top of this page — it updates in real time and already accounts for the -4h 30m offset from Mumbai.

What is the best time to call BST from Mumbai?

Call between 1:30 PM and 5:00 PM IST — that maps to 9:00 AM–12:30 PM BST and keeps both parties inside the working day.

Which is behind, Mumbai or BST?

Mumbai is 4 hours 30 minutes behind BST. When it is 12:00 PM in Mumbai it is 7:30 AM in BST.

Do Mumbai and BST use different time zones?

Mumbai (India) uses IST at UTC+05:30, while BST uses BST at UTC+01:00. The IANA identifiers are Asia/Kolkata and Europe/London.

Does daylight saving time affect the Mumbai–BST difference?

Neither zone observes daylight saving time, so the -4h 30m offset between Mumbai and BST is fixed all year.

Which other cities share Mumbai's time zone?

IST also covers Mumbai, Delhi, Bangalore, Kolkata, Chennai, Hyderabad, Pune, Ahmedabad and 4 more.

Which countries use IST, Mumbai's zone?

IST is used in India, Sri Lanka.

Is there a day difference between Mumbai and BST?

Not normally. The -4h 30m gap only pushes the date over the previous day.

What is the time difference between Mumbai and BST?

BST is -4h 30m from Mumbai.

What timezone is Mumbai in?

Mumbai operates on India Standard Time (IST), UTC+5:30. As India's financial capital and home to BSE (Asia's oldest stock exchange), Mumbai timing is crucial for Asia markets.