BST to Colombo
+4h 30mBST
BSTSOURCEColombo
ISTGreen rows indicate typical business hours (9 AM - 5 PM)
BST and IST on the World Map
The map below highlights the BST (British Summer Time) and IST (India Standard Time) timezone regions across the globe.
BST – British Summer Time
UTC+01:00British Summer Time (BST, UTC+01:00) is the daylight saving period in the United Kingdom, running from late March to late October.
- •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.
IST – India Standard Time
UTC+05:30India Standard Time (IST) is the time zone for India and Sri Lanka, 5 hours and 30 minutes ahead of UTC.
- •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.
About Colombo
WikipediaColombo operates on Sri Lanka Time (SLST), UTC+5:30. Sharing India's timezone, Colombo is a key South Asian trade and tourism hub.
Sri Lanka Standard Time (SLST) uses UTC+5:30, same offset as India.
Understanding the +4h 30m Gap: BST vs Colombo
BST runs on British Summer Time (BST) at UTC+01:00. Colombo runs on India Standard Time (IST) at UTC+05:30. That puts BST 4 hours 30 minutes ahead of Colombo — a difference of +4h 30m at the current offsets.
In practice, when it is 9:00 AM in BST it is 1:30 PM in Colombo. Midnight in BST is 4:30 AM in Colombo. Neither zone observes daylight saving time, so the offset between them stays constant all year.
BST to Colombo time conversion table
| BST (BST) | Colombo (IST) | Day |
|---|---|---|
| 12:00 AM | 4:30 AM | same day |
| 6:00 AM | 10:30 AM | same day |
| 7:00 AM | 11:30 AM | same day |
| 8:00 AM | 12:30 PM | same day |
| 9:00 AM | 1:30 PM | same day |
| 12:00 PM | 4:30 PM | same day |
| 3:00 PM | 7:30 PM | same day |
| 5:00 PM | 9:30 PM | same day |
| 6:00 PM | 10:30 PM | same day |
| 9:00 PM | 1:30 AM | next day |
Why people convert BST to Colombo time
- Scheduling a call from BST to Colombo: a 10:00 AM start in BST lands at 2:30 PM in Colombo, so you can confirm the slot without doing the arithmetic yourself.
- Finding shared working hours: both BST and Colombo are inside the 9-to-5 working day between 9:00 AM and 12:30 PM BST time (1:30 PM–5:00 PM IST). That is roughly 3 hours 30 minutes of usable overlap.
- Coordinating a BST-based team with Colombo 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 +4h 30m gap is not.
- Block 9:00 AM–12:30 PM BST as the recurring meeting window if you work primarily from BST and need Colombo colleagues present.
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 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.
Best time to call between BST and Colombo
Both BST and Colombo sit inside the 9 AM – 5 PM working day between 9:00 AM–12:30 PM BST, which is 1:30 PM–5:00 PM IST. That gives roughly 3 hours and 30 minutes of shared time — the safest window for a live call or meeting.
Business hours overlap
BST and Colombo overlap for about 3 hours during the working day — enough for meetings if you avoid the edges of the window.
BST is 4 hours 30 minutes ahead of Colombo (BST UTC+01:00 → IST UTC+05:30). The shared working window is 9:00 AM–12:30 PM BST. 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
Colombo
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:
Frequently Asked Questions
What is the time difference between BST and Colombo?
BST (BST, UTC+01:00) is 4 hours 30 minutes ahead of Colombo (IST, UTC+05:30). The gap is currently +4h 30m.
How do I convert BST time to Colombo time?
Add +4h 30m to BST local time. For example, 9:00 AM in BST is 1:30 PM in Colombo.
What time is it in Colombo right now?
Colombo uses IST at UTC+05:30. Use the live converter at the top of this page — it updates in real time and already accounts for the +4h 30m offset from BST.
What is the best time to call Colombo from BST?
Call between 9:00 AM and 12:30 PM BST — that maps to 1:30 PM–5:00 PM IST and keeps both parties inside the working day.
Which is ahead, BST or Colombo?
BST is 4 hours 30 minutes ahead of Colombo. When it is 12:00 PM in BST it is 4:30 PM in Colombo.
Do BST and Colombo use different time zones?
BST uses BST at UTC+01:00, while Colombo (Sri Lanka) uses IST at UTC+05:30. The IANA identifiers are Europe/London and Asia/Colombo.
Does daylight saving time affect the BST–Colombo difference?
Neither zone observes daylight saving time, so the +4h 30m offset between BST and Colombo is fixed all year.
Which other cities share BST's time zone?
BST also covers London, Birmingham, Manchester, Glasgow, Edinburgh, Cardiff, Belfast, Liverpool and 2 more.
Which countries use BST, BST's zone?
BST is used in United Kingdom.
Is there a day difference between BST and Colombo?
Not normally. The +4h 30m gap only pushes the date over for late-evening times.
What is the time difference between BST and Colombo?
Colombo is +4h 30m from BST.
What timezone is BST in?
BST operates on its local timezone.
What timezone is Colombo in?
Colombo operates on Sri Lanka Time (SLST), UTC+5:30. Sharing India's timezone, Colombo is a key South Asian trade and tourism hub.
What are the business hours in Colombo?
Standard business hours in Colombo are 9:00 AM - 5:00 PM IST.
Which countries use BST (British Summer Time)?
BST is used in United Kingdom.
Does BST observe daylight saving time?
Yes, BST switches to BST during summer months.
What are some interesting 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.
Which cities are in the IST timezone?
Major cities in the IST timezone include Mumbai, Delhi, Bangalore, Kolkata, Chennai, Hyderabad, Pune, Ahmedabad.
What is the UTC offset for IST?
India Standard Time (IST) is at UTC+05:30.
What should I know about the IST timezone?
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.
When is it midnight in BST, what time is it in Colombo?
When it is 12:00 AM (midnight) in BST (BST), it is +4h 30m later in Colombo (IST).
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