Time Difference: Kolkata vs London
London is 4.5 hours behind Kolkata.
Quick Reference
- Kolkata
- IST (GMT+5:30)
No Daylight Saving Time
- London
- BST (GMT+1)
GMT starts on Oct 25, 2026
Frequently Asked Questions
- What is the time difference between Kolkata and London?
- London is 4.5 hours behind Kolkata.
- When is the best time to call from Kolkata to London?
- The best time to call is during overlapping business hours (9 AM – 5 PM) in both cities. Use the interactive converter on this page to visually compare hours side by side.
- Does the time difference change with daylight saving time?
- The time difference may change when either city enters or exits daylight saving time. Kolkata uses IST and London uses BST.