IRST to Sri Lanka
+2hIRST
IRSTSOURCESri Lanka
ISTGreen rows indicate typical business hours (9 AM - 5 PM)
IRST and IST on the World Map
The map below highlights the IRST (Iran Standard Time) and IST (India Standard Time) timezone regions across the globe.
IRST – Iran Standard Time
UTC+03:30Iran Standard Time (IRST) is the time zone for Iran, 3 hours and 30 minutes ahead of UTC.
- •IRST is one of only a few time zones with a 30-minute offset.
- •Iran observes daylight saving time, switching to IRDT (UTC+04:30).
- •Tehran has a metropolitan population of over 16 million.
IST – India Standard Time
UTC+05:30India Standard Time (IST) is the time zone for India and Sri Lanka, 5 hours and 30 minutes ahead of UTC.
- •India is 10 hours 30 minutes ahead of EST and 5 hours 30 minutes ahead of GMT.
- •India uses a single time zone despite spanning 30° of longitude.
- •IST is one of only a handful of time zones with a 30-minute offset.
- •IST is the most populous single time zone in the world with over 1.4 billion people.
- •The Bombay Stock Exchange (BSE) and National Stock Exchange (NSE) operate on IST.
IRST vs Sri Lanka: Offsets, DST and Best Call Times
IRST runs on Iran Standard Time (IRST) at UTC+03:30. Sri Lanka runs on India Standard Time (IST) at UTC+05:30. That puts IRST 2 hours ahead of Sri Lanka — a difference of +2h at the current offsets.
In practice, when it is 9:00 AM in IRST it is 11:00 AM in Sri Lanka. Midnight in IRST is 2:00 AM in Sri Lanka. Neither zone observes daylight saving time, so the offset between them stays constant all year.
IRST to Sri Lanka time conversion table
| IRST (IRST) | Sri Lanka (IST) | Day |
|---|---|---|
| 12:00 AM | 2:00 AM | same day |
| 6:00 AM | 8:00 AM | same day |
| 7:00 AM | 9:00 AM | same day |
| 8:00 AM | 10:00 AM | same day |
| 9:00 AM | 11:00 AM | same day |
| 12:00 PM | 2:00 PM | same day |
| 3:00 PM | 5:00 PM | same day |
| 5:00 PM | 7:00 PM | same day |
| 6:00 PM | 8:00 PM | same day |
| 9:00 PM | 11:00 PM | same day |
Why people convert IRST to Sri Lanka time
- Scheduling a call from IRST to Sri Lanka: a 10:00 AM start in IRST lands at 12:00 PM in Sri Lanka, so you can confirm the slot without doing the arithmetic yourself.
- Finding shared working hours: both IRST and Sri Lanka are inside the 9-to-5 working day between 9:00 AM and 3:00 PM IRST time (11:00 AM–5:00 PM IST). That is roughly 6 hours of usable overlap.
- Watching a live event or market open: IRST viewers need 11:00 AM in Sri Lanka to catch a 9:00 AM start there, and 10:00 PM if the event is anchored to IRST.
- Always state the zone abbreviation, not just the hour. "3:00 PM IRST" is unambiguous; "3 PM" across a +2h gap is not.
- Block 9:00 AM–3:00 PM IRST as the recurring meeting window if you work primarily from IRST and need Sri Lanka colleagues present.
About IRST (Iran Standard Time)
Iran Standard Time (IRST) is one of the few time zones with a 30-minute offset. Iran observes daylight saving time (IRDT, UTC+04:30) from late March to late September. Tehran, the capital, is one of the largest cities in the Middle East.
About IST (India Standard Time)
India Standard Time (IST) is the time observed throughout India and Sri Lanka. It is based on the 82.5°E meridian, passing through Mirzapur in Uttar Pradesh. India uses a single time zone despite spanning roughly 30° of longitude, which has been debated. IST does not observe daylight saving time. India is the world's most populous country, making IST one of the most-used time zones globally. The IT outsourcing industry and call centers operate primarily on IST, making the EST-to-IST conversion one of the most searched timezone conversions.
Best time to call between IRST and Sri Lanka
Both IRST and Sri Lanka sit inside the 9 AM – 5 PM working day between 9:00 AM–3:00 PM IRST, which is 11:00 AM–5:00 PM IST. That gives roughly 6 hours of shared time — the safest window for a live call or meeting.
Business hours overlap
IRST and Sri Lanka share 6 hours of working-hours overlap (9:00 AM–3:00 PM IRST), so scheduling a live meeting is straightforward.
IRST is 2 hours ahead of Sri Lanka (IRST UTC+03:30 → IST UTC+05:30). The shared working window is 9:00 AM–3:00 PM IRST. Remember to re-check around daylight-saving transitions.
Learn More About Time
Dive deeper into the fascinating world of timekeeping, time zones, and how they shape our global society:
Frequently Asked Questions
What is the time difference between IRST and Sri Lanka?
IRST (IRST, UTC+03:30) is 2 hours ahead of Sri Lanka (IST, UTC+05:30). The gap is currently +2h.
How do I convert IRST time to Sri Lanka time?
Add +2h to IRST local time. For example, 9:00 AM in IRST is 11:00 AM in Sri Lanka.
What time is it in Sri Lanka right now?
Sri Lanka uses IST at UTC+05:30. Use the live converter at the top of this page — it updates in real time and already accounts for the +2h offset from IRST.
What is the best time to call Sri Lanka from IRST?
Call between 9:00 AM and 3:00 PM IRST — that maps to 11:00 AM–5:00 PM IST and keeps both parties inside the working day.
Which is ahead, IRST or Sri Lanka?
IRST is 2 hours ahead of Sri Lanka. When it is 12:00 PM in IRST it is 2:00 PM in Sri Lanka.
Do IRST and Sri Lanka use different time zones?
IRST uses IRST at UTC+03:30, while Sri Lanka (Sri Lanka) uses IST at UTC+05:30. The IANA identifiers are Asia/Tehran and Asia/Colombo.
Does daylight saving time affect the IRST–Sri Lanka difference?
Neither zone observes daylight saving time, so the +2h offset between IRST and Sri Lanka is fixed all year.
Which other cities share IRST's time zone?
IRST also covers Tehran, Isfahan, Mashhad, Tabriz, Shiraz, Karaj.
Which countries use IRST, IRST's zone?
IRST is used in Iran.
Is there a day difference between IRST and Sri Lanka?
Not normally. The +2h gap only pushes the date over for late-evening times.
What is the time difference between IRST and Sri Lanka?
Sri Lanka is +2h from IRST.
What timezone is IRST in?
IRST operates on its local timezone.
What timezone is Sri Lanka in?
Sri Lanka operates on its local timezone.
Which countries use IRST (Iran Standard Time)?
IRST is used in Iran.
Does IRST observe daylight saving time?
Yes, IRST switches to IRDT during summer months.
What are some interesting facts about IRST?
IRST is one of only a few time zones with a 30-minute offset. Iran observes daylight saving time, switching to IRDT (UTC+04:30).
Which cities are in the IST timezone?
Major cities in the IST timezone include Mumbai, Delhi, Bangalore, Kolkata, Chennai, Hyderabad, Pune, Ahmedabad.
What is the UTC offset for IST?
India Standard Time (IST) is at UTC+05:30.
What should I know about the IST timezone?
India is 10 hours 30 minutes ahead of EST and 5 hours 30 minutes ahead of GMT. India uses a single time zone despite spanning 30° of longitude.
When is it midnight in IRST, what time is it in Sri Lanka?
When it is 12:00 AM (midnight) in IRST (IRST), it is +2h later in Sri Lanka (IST).
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