Best overlap: 11:30 AM to 6:30 PM in Kolkata is 8:00 AM to 3:00 PM in Madrid.
Both offices are open during 11:30 AM to 6:30 PM Kolkata time, which is 8:00 AM to 3:00 PM in Madrid. Madrid is 3.5 hours behind Kolkata, and with 7 hours of overlap you can even run back-to-back calls without stepping outside business hours. Because only Madrid changes its clocks, the overlap above isn't fixed; expect a one-hour shift when Madrid 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 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Kolkata Asia/Kolkata | ||||||||||||||||||||||||
Madrid Europe/Madrid |
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. -