Best overlap: 8:00 AM to 4:00 PM in Helsinki is 10:30 AM to 6:30 PM in Kolkata.
8:00 AM to 4:00 PM in Helsinki is when Kolkata is also working, at 10:30 AM to 6:30 PM their time. Even with Kolkata ahead by 2.5 hours, your workdays overlap by a comfortable 8 hours — plenty of flexibility for both sides. Because only Helsinki changes its clocks, the overlap above isn't fixed; expect a one-hour shift when Helsinki enters or leaves daylight saving.
| Local time | 12am | 1am | 2am | 3am | 4am | 5am | 6am | 7am | 8am | 9am | 10am | 11am | 12pm | 1pm | 2pm | 3pm | 4pm | 5pm | 6pm | 7pm | 8pm | 9pm | 10pm | 11pm |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Helsinki Europe/Helsinki | ||||||||||||||||||||||||
Kolkata Asia/Kolkata |
A complete guide to time zones in 2025, from UTC and GMT differences to Daylight Saving Time changes, IANA database rules, abbreviation pitfalls, and developer best practices for handling global time. -