London, United Kingdom Kolkata, India

London is in the BST timezone (UTC+1) and Kolkata is in the IST timezone (UTC+5:30). The time difference between them is 4h 30m.

Use the timeline above to find overlapping business hours between London and Kolkata. The "Best time to meet" card highlights the window where both cities are within working hours (9 AM – 6 PM local time).

London observes Daylight Saving Time, while Kolkata does not. When DST is active in London, the time difference changes by 1 hour.

Click the pencil icon next to the London clock and type any time. The Kolkata clock will update instantly, showing the exact corresponding time. You can also pick a date to account for DST changes.