Colombo to Tehran Time
IST to IRST Converter — 9 AM IST is 7:00 AM IRST
Colombo is 2 hours ahead of Tehran. Convert any time between Colombo (IST) and Tehran (IRST/IRDT) instantly.
Colombo
Sri Lanka
Tehran
Iran
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Time Zone Comparison
Colombo to Tehran Time Conversion Table
| Colombo (IST) | Tehran (IRST) |
|---|---|
| 12:00 AM | 10:00 PM |
| 2:00 AM | 12:00 AM |
| 4:00 AM | 2:00 AM |
| 6:00 AM | 4:00 AM |
| 8:00 AM | 6:00 AM |
| 10:00 AM | 8:00 AM |
| 12:00 PM | 10:00 AM |
| 2:00 PM | 12:00 PM |
| 4:00 PM | 2:00 PM |
| 6:00 PM | 4:00 PM |
| 8:00 PM | 6:00 PM |
| 10:00 PM | 8:00 PM |
Colombo & Tehran — Business & Scheduling Guide
Colombo (Sri Lanka) is a South Asian island economy with strategic Indian Ocean positioning, with key industries in tourism, tea, apparel, and IT/BPO services. Tehran (Iran) is one of the Middle East's largest economies with a young population, known for oil and gas, petrochemicals, automotive, and agriculture. With a 2-hour time difference, professionals frequently schedule cross-border calls between these two cities for international trade, remote team collaboration, and client meetings.
Scheduling Meetings Between Colombo and Tehran
With only a 2-hour gap, Colombo and Tehran have generous overlapping work hours. Morning calls in the earlier time zone align well with mid-day in the other. Sri Lankan business hours are typically 8:30 AM–5 PM, with a growing technology outsourcing sector. Iranian business hours are typically 8 AM–4 PM Saturday–Wednesday, with Thursday as a half-day and Friday off. Most teams find that late morning to early afternoon offers the widest window for collaboration.
Daylight Saving Time Considerations
Tehran observes Daylight Saving Time (IRST/IRDT), while Colombo stays on IST year-round. When Tehran switches to daylight time, the effective time difference shifts by 1 hour. This typically happens in spring and fall, and the exact dates vary by country. If you have recurring cross-timezone meetings, recalculate the schedule after each DST transition.
Collaboration Tools & Workflow
Teams working between Colombo and Tehran enjoy strong real-time collaboration potential. With just a 2-hour time difference, daily standups, pair programming, and spontaneous video calls are all practical. Popular tools for Colombo–Tehran teams include Slack for real-time messaging, Google Meet or Zoom for video calls, and Notion or Linear for project management. The overlapping work window is wide enough that most teams can operate nearly synchronously.
Remote Work Between Colombo & Tehran
Colombo, a key city in Sri Lanka, and Tehran, a key city in Iran, are well-connected for remote work. With a manageable 2-hour time difference, distributed teams can maintain a near-synchronous workflow. Both cities have strong internet infrastructure, coworking spaces, and established remote work cultures. For freelancers and remote workers, this time zone pairing is ideal — you can serve clients in Tehran from Colombo (or vice versa) without disrupting your standard workday.
IST to IRST — Quick Reference
IST (IST) stands for the timezone used in Colombo, Sri Lanka (UTC+5:30). IRST (IRST/IRDT) is the timezone used in Tehran, Iran (UTC+3:30). Colombo is 2 hours ahead of Tehran.
To convert IST to IRST, subtract 2 hours from IST time. For example, IST 9:00 AM = IRST 7:00 AM.
Key Facts
- •Time difference: Colombo (UTC+5:30) is 2 hours ahead of Tehran (UTC+3:30).
- •Daylight Saving Time: Colombo does not observe DST (IST). Tehran observes DST (IRST/IRDT).
- •Regions: Colombo is located in Sri Lanka and uses the IST time zone. Tehran is located in Iran and uses the IRST/IRDT time zone.
- •Best time to call: The best time to call between Colombo and Tehran is 11:00 AM to 4:00 PM in Colombo time, when both cities have overlapping standard working hours.
Frequently Asked Questions
What is the time difference between Colombo and Tehran?
Colombo is 2 hours ahead of Tehran.
What time is it in Tehran when it's 9 AM in Colombo?
When it's 9:00 AM in Colombo, it is 7:00 AM in Tehran.
What time is 9 PM IST in IRST?
9 PM IST (Colombo time) is 7:00 PM IRST (Tehran time). This is a common time people check when scheduling evening calls across these two time zones.
When is the best time to schedule a meeting between Colombo and Tehran?
The best time to schedule a meeting is between 11:00 AM to 4:00 PM in Colombo time, when both cities are within standard working hours (9 AM – 5 PM). This gives you the maximum overlap window for real-time collaboration.
How do I convert IST to IRST?
IST (IST) is the timezone for Colombo, Sri Lanka (UTC+5:30). IRST (IRST/IRDT) is the timezone for Tehran, Iran (UTC+3:30). Colombo is 2 hours ahead of Tehran. Quick examples: 9 AM IST = 7:00 AM IRST, 12 PM IST = 10:00 AM IRST, 3 PM IST = 1:00 PM IRST, 6 PM IST = 4:00 PM IRST.
Is Colombo ahead of or behind Tehran?
Colombo is 2 hours ahead of Tehran. When it's noon in Colombo, it's 10:00 AM in Tehran.
Does Colombo or Tehran change clocks for Daylight Saving Time?
No, Colombo does not observe DST — it stays on IST year-round. Tehran observes DST and switches between IRST/IRDT. Because only one city observes DST, the time difference shifts by 1 hour during transition periods (typically March/April and October/November).
What time is noon in Colombo in Tehran time?
When it is 12:00 PM (noon) in Colombo (IST), it is 10:00 AM in Tehran (IRST). This is often a popular time for scheduling lunch-hour calls across the Colombo–Tehran corridor.
What are the overlapping work hours between Colombo and Tehran?
The overlapping work hours between Colombo and Tehran are approximately 11:00 AM to 4:00 PM in Colombo time, when both cities are within the standard 9 AM–5 PM workday. This is the ideal window for meetings, pair programming, and real-time collaboration.
What timezone is Colombo in?
Colombo is in the IST time zone (UTC+5:30). It is located in Sri Lanka. Colombo does not observe Daylight Saving Time.
What timezone is Tehran in?
Tehran is in the IRST/IRDT time zone (UTC+3:30). It is located in Iran. Tehran observes Daylight Saving Time, switching between IRST/IRDT.
How do I schedule a call between Colombo and Tehran?
To schedule a call between Colombo and Tehran, aim for the overlapping window of 11:00 AM to 4:00 PM in Colombo time. Use Google Calendar or Calendly with both time zones visible, share the meeting invite with the IRST time clearly noted, and always double-check the time difference — especially during DST transitions. Pro tip: include both local times in the calendar invite title (e.g., "Sync — 10 AM IST / 8:00 AM IRST").
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