Kolkata to London Time

Kolkata is 4 hours 30 minutes ahead of London.

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Kolkata time to London time

Kolkata is 4 hours 30 minutes ahead of London. When it is 9:00 AM in Kolkata, India, it is 4:30 AM in London, UK. Standard 9 AM to 6 PM working hours overlap for 4 hours 30 minutes: 1:30 PM to 6:00 PM in Kolkata (9:00 AM to 1:30 PM in London).

Time difference

4 hours 30 minutes (Kolkata ahead). Kolkata uses IST; London uses BST.

Working-hours overlap

4 hours 30 minutes of shared 9 AM to 6 PM hours.

Daylight saving

Next change: Sun, Oct 25, 2026 (London).

Kolkata to London time conversion table

Times for Fri, Oct 9, 2026. Highlighted rows fall within 9 AM to 6 PM in both cities. Drag the live converter above for any other date.
Kolkata (IST)London (BST)
12:00 AM7:30 PM (previous day)
1:00 AM8:30 PM (previous day)
2:00 AM9:30 PM (previous day)
3:00 AM10:30 PM (previous day)
4:00 AM11:30 PM (previous day)
5:00 AM12:30 AM
6:00 AM1:30 AM
7:00 AM2:30 AM
8:00 AM3:30 AM
9:00 AM4:30 AM
10:00 AM5:30 AM
11:00 AM6:30 AM
12:00 PM7:30 AM
1:00 PM8:30 AM
2:00 PM9:30 AM
3:00 PM10:30 AM
4:00 PM11:30 AM
5:00 PM12:30 PM
6:00 PM1:30 PM
7:00 PM2:30 PM
8:00 PM3:30 PM
9:00 PM4:30 PM
10:00 PM5:30 PM
11:00 PM6:30 PM

Daylight saving time

On Sun, Oct 25, 2026, London switches from BST to GMT, so the difference becomes 5 hours 30 minutes (Kolkata ahead). On Sun, Mar 28, 2027, London switches from GMT to BST, so the difference becomes 4 hours 30 minutes (Kolkata ahead).

How to use the meeting time converter

  1. Select either city name and search by city, time zone, abbreviation, or UTC offset.
  2. Drag the horizontal timeline, or use the arrow and Page Up/Page Down keys, to choose a moment.
  3. Read the matching time and date for both locations and use the color bands to compare working hours.

Frequently asked questions

What is the time difference between Kolkata and London?

Kolkata is 4 hours 30 minutes ahead of London. Kolkata currently uses IST and London uses BST.

When it is 9 AM in Kolkata, what time is it in London?

It is 4:30 AM in London.

What is the best time for a meeting between Kolkata and London?

Standard 9 AM to 6 PM working hours overlap for 4 hours 30 minutes: 1:30 PM to 6:00 PM in Kolkata (9:00 AM to 1:30 PM in London).

Does daylight saving time affect Kolkata and London?

On Sun, Oct 25, 2026, London switches from BST to GMT, so the difference becomes 5 hours 30 minutes (Kolkata ahead). On Sun, Mar 28, 2027, London switches from GMT to BST, so the difference becomes 4 hours 30 minutes (Kolkata ahead).

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