Istanbul zone
GMT+3 (GMT+3)
Kolkata zone
GMT+5:30 (GMT+5:30)
Difference
2h 30m ahead of Istanbul
Business overlap
6h (9-5 windows)
Working hours overlap
Each cell is one hour in Istanbul. Filled cells mark when 9 AM – 5 PM in Istanbul and Kolkata both apply.
6 hours per day
- Istanbul
- GMT+3
- Kolkata
- GMT+5:30
- Difference
- +2h 30m
- Business overlap
- 6h
Hour-by-hour conversion
Each row shows the matching local time in Kolkata for an hour in Istanbul.
| Istanbul | Kolkata | Day | Window |
|---|---|---|---|
| 12:00 AM | 2:30 AM | same day | — |
| 1:00 AM | 3:30 AM | same day | — |
| 2:00 AM | 4:30 AM | same day | — |
| 3:00 AM | 5:30 AM | same day | — |
| 4:00 AM | 6:30 AM | same day | — |
| 5:00 AM | 7:30 AM | same day | — |
| 6:00 AM | 8:30 AM | same day | — |
| 7:00 AM | 9:30 AM | same day | — |
| 8:00 AM | 10:30 AM | same day | — |
| 9:00 AM | 11:30 AM | same day | Both 9-5 |
| 10:00 AM | 12:30 PM | same day | Both 9-5 |
| 11:00 AM | 1:30 PM | same day | Both 9-5 |
| 12:00 PM | 2:30 PM | same day | Both 9-5 |
| 1:00 PM | 3:30 PM | same day | Both 9-5 |
| 2:00 PM | 4:30 PM | same day | Both 9-5 |
| 3:00 PM | 5:30 PM | same day | — |
| 4:00 PM | 6:30 PM | same day | — |
| 5:00 PM | 7:30 PM | same day | — |
| 6:00 PM | 8:30 PM | same day | — |
| 7:00 PM | 9:30 PM | same day | — |
| 8:00 PM | 10:30 PM | same day | — |
| 9:00 PM | 11:30 PM | same day | — |
| 10:00 PM | 12:30 AM | next day | — |
| 11:00 PM | 1:30 AM | next day | — |
Best meeting windows
If both teams keep standard 9 AM – 5 PM hours, the overlap window is roughly 9:00 AM – 3:00 PM in Istanbul time. That gives you 6 hours per workday for live meetings.
Tighter overlap is achievable by having the side with later working hours start earlier, or by treating the first and last hours of each side as flexible. The bar above marks every hour where both cities sit inside a 9 AM – 5 PM window.
About converting Istanbul time to Kolkata time
Istanbul follows the Europe/Istanbul time zone (currently GMT+3, GMT+3), while Kolkata follows Asia/Kolkata (currently GMT+5:30, GMT+5:30). Kolkata is 2h 30m ahead of Istanbul right now.
Neither city observes daylight saving time, so the offset between them is the same all year.
Reverse this conversion
Kolkata to Istanbul
Open the converter
Plan a meeting between Istanbul and Kolkata
More conversions from Istanbul
Frequently asked questions
- How many hours is Istanbul from Kolkata?
- Kolkata is 2h 30m ahead of Istanbul right now.
- What time is 9:00 AM Istanbul in Kolkata?
- 9:00 AM in Istanbul is 11:30 AM in Kolkata.
- What time is 5:00 PM Istanbul in Kolkata?
- 5:00 PM in Istanbul is 7:30 PM in Kolkata.
- When do Istanbul and Kolkata business hours overlap?
- Standard 9 AM - 5 PM working hours overlap for about 6 hours, roughly from 9:00 AM to 3:00 PM in Istanbul time.
- Does daylight saving time change the difference between Istanbul and Kolkata?
- Neither Istanbul nor Kolkata observes daylight saving time, so the offset between them is constant year-round.
Local time page
Time in Istanbul
Local time page
Time in Kolkata