Kolkata to London Time
Live IST ↔ GMT/BST time converter · West Bengal, India → UK DST applies
24-Hour Overlap Timeline
⚠ London observes daylight saving time — offset shifts between UTC+0 and UTC+1 seasonally
| 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| UTC → | ||||||||||||||||||||||||
| 🇮🇳 Kolkata UTC+5:30 | 5a | 6a | 7a | 8a | 9a | 10a | 11a | 12p | 1p | 2p | 3p | 4p | 5p | 6p | 7p | 8p | 9p | 10p | 11p | 12a | 1a | 2a | 3a | 4a |
| 🇬🇧 London UTC+0 | 12a | 1a | 2a | 3a | 4a | 5a | 6a | 7a | 8a | 9a | 10a | 11a | 12p | 1p | 2p | 3p | 4p | 5p | 6p | 7p | 8p | 9p | 10p | 11p |
IST (Indian Standard Time) to London (GMT (Greenwich Mean Time)/BST (British Summer Time)) Conversion Table
All 24 hours of the day · based on standard time — GMT (Greenwich Mean Time).
Live offset may differ during DST (BST (British Summer Time)) — see clock above.
✅ Both in business hours 🔵 India office hours only 🟢 London office hours only
| IST (Indian Standard Time) — Kolkata | London — GMT/BST | Working hours |
|---|---|---|
| 12:00 AM IST (Indian Standard Time) | 6:30 PM GMT | −1 day |
| 1:00 AM IST (Indian Standard Time) | 7:30 PM GMT | −1 day |
| 2:00 AM IST (Indian Standard Time) | 8:30 PM GMT | −1 day |
| 3:00 AM IST (Indian Standard Time) | 9:30 PM GMT | −1 day |
| 4:00 AM IST (Indian Standard Time) | 10:30 PM GMT | −1 day |
| 5:00 AM IST (Indian Standard Time) | 11:30 PM GMT | −1 day |
| 6:00 AM IST (Indian Standard Time) | 12:30 AM GMT | |
| 7:00 AM IST (Indian Standard Time) | 1:30 AM GMT | |
| 8:00 AM IST (Indian Standard Time) | 2:30 AM GMT | |
| 9:00 AM IST (Indian Standard Time) | 3:30 AM GMT | 🔵 India only |
| 10:00 AM IST (Indian Standard Time) | 4:30 AM GMT | 🔵 India only |
| 11:00 AM IST (Indian Standard Time) | 5:30 AM GMT | 🔵 India only |
| 12:00 PM IST (Indian Standard Time) | 6:30 AM GMT | 🔵 India only |
| 1:00 PM IST (Indian Standard Time) | 7:30 AM GMT | 🔵 India only |
| 2:00 PM IST (Indian Standard Time) | 8:30 AM GMT | 🔵 India only |
| 3:00 PM IST (Indian Standard Time) | 9:30 AM GMT | ✅ overlap |
| 4:00 PM IST (Indian Standard Time) | 10:30 AM GMT | ✅ overlap |
| 5:00 PM IST (Indian Standard Time) | 11:30 AM GMT | ✅ overlap |
| 6:00 PM IST (Indian Standard Time) | 12:30 PM GMT | 🟢 GMT only |
| 7:00 PM IST (Indian Standard Time) | 1:30 PM GMT | 🟢 GMT only |
| 8:00 PM IST (Indian Standard Time) | 2:30 PM GMT | 🟢 GMT only |
| 9:00 PM IST (Indian Standard Time) | 3:30 PM GMT | 🟢 GMT only |
| 10:00 PM IST (Indian Standard Time) | 4:30 PM GMT | 🟢 GMT only |
| 11:00 PM IST (Indian Standard Time) | 5:30 PM GMT |
Explore Kolkata — Top Attractions & Travel Guide
Discover top attractions, local tips and hidden gems in Kolkata on india-guide.in — India's curated travel destination guide.
Explore Kolkata on india-guide.in →Best Time to Call London from Kolkata
Both Kolkata and London are in standard business hours simultaneously during this window. Schedule meetings, investor calls, or client demos in this slot for maximum availability.
⏰ DST reminder: During BST (late Mar–late Oct) London is only 4h 30m behind IST instead of 5h 30m. Indian offices often schedule London calls at 1:30 PM IST (9 AM BST in summer, but 8 AM GMT in winter — important for early-morning London meetings).
Kolkata, India
Kolkata is eastern India's commercial and cultural hub, and serves as the gateway to north-east India and Bangladesh. The city's jute, tea, and coal trade built British India. Today it houses the Calcutta Stock Exchange and is a growing IT destination. Kolkata's intellectual and literary tradition makes it India's cultural capital. It is the closest major Indian city to South-East Asia, with strong historic trade ties.
- Gateway to North-East India and Bangladesh
- Calcutta Stock Exchange — India's second oldest
- India's dominant jute, tea, and coal trading centre historically
- Closest major India city to South-East Asian markets
London, UK
London is the UK's capital and one of the world's top financial centres. The London Stock Exchange, Bank of England, and thousands of global banks make it the primary European hub for Indian finance. The UK hosts the largest Indian diaspora outside the subcontinent — over 1.5 million people of Indian origin call the UK home. Indian companies listed on the LSE range from Tata Steel to HDFC.
- UK capital and global financial centre
- Largest Indian diaspora in Europe
- London Stock Exchange lists Tata, HDFC
- Direct flights from 6 Indian cities
Frequently Asked Questions
What is the time difference between Kolkata and London?
When do clocks change in London and how does it affect IST?
During BST (late Mar–late Oct) London is only 4h 30m behind IST instead of 5h 30m. Indian offices often schedule London calls at 1:30 PM IST (9 AM BST in summer, but 8 AM GMT in winter — important for early-morning London meetings).