Colombo to GST
-1h 30mColombo
ISTSOURCEGST
GSTGreen rows indicate typical business hours (9 AM - 5 PM)
IST and GST on the World Map
The map below highlights the IST (India Standard Time) and GST (Gulf Standard Time) timezone regions across the globe.
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.
GST – Gulf Standard Time
UTC+04:00Gulf Standard Time (GST) is used in the UAE, Oman, and other Gulf states, 4 hours ahead of UTC.
- •Dubai uses GST year-round with no daylight saving time.
- •GST is 9 hours ahead of EST and 4 hours ahead of GMT.
- •The Dubai Financial Market (DFM) operates on GST.
About Colombo
WikipediaColombo operates on Sri Lanka Time (SLST), UTC+5:30. Sharing India's timezone, Colombo is a key South Asian trade and tourism hub.
Sri Lanka Standard Time (SLST) uses UTC+5:30, same offset as India.
Colombo to GST Time Difference – Complete Guide
Colombo runs on India Standard Time (IST) at UTC+05:30. GST runs on Gulf Standard Time (GST) at UTC+04:00. That puts Colombo 1 hour 30 minutes behind GST — a difference of -1h 30m at the current offsets.
In practice, when it is 9:00 AM in Colombo it is 7:30 AM in GST. Midnight in Colombo is 10:30 PM in GST. Neither zone observes daylight saving time, so the offset between them stays constant all year.
Colombo to GST time conversion table
| Colombo (IST) | GST (GST) | Day |
|---|---|---|
| 12:00 AM | 10:30 PM | previous day |
| 6:00 AM | 4:30 AM | same day |
| 7:00 AM | 5:30 AM | same day |
| 8:00 AM | 6:30 AM | same day |
| 9:00 AM | 7:30 AM | same day |
| 12:00 PM | 10:30 AM | same day |
| 3:00 PM | 1:30 PM | same day |
| 5:00 PM | 3:30 PM | same day |
| 6:00 PM | 4:30 PM | same day |
| 9:00 PM | 7:30 PM | same day |
Why people convert Colombo to GST time
- Scheduling a call from Colombo to GST: a 10:00 AM start in Colombo lands at 8:30 AM in GST, so you can confirm the slot without doing the arithmetic yourself.
- Finding shared working hours: both Colombo and GST are inside the 9-to-5 working day between 10:30 AM and 5:00 PM IST time (9:00 AM–3:30 PM GST). That is roughly 6 hours 30 minutes of usable overlap.
- Watching a live event or market open: Colombo viewers need 7:30 AM in GST to catch a 9:00 AM start there, and 1:30 AM if the event is anchored to Colombo.
- Always state the zone abbreviation, not just the hour. "3:00 PM IST" is unambiguous; "3 PM" across a -1h 30m gap is not.
- Block 10:30 AM–5:00 PM IST as the recurring meeting window if you work primarily from Colombo and need GST colleagues present.
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.
About GST (Gulf Standard Time)
Gulf Standard Time (GST) is the time zone used in the United Arab Emirates, Oman, and other Gulf states. GST does not observe daylight saving time. Dubai and Abu Dhabi, major international business and tourism hubs, operate on GST.
Best time to call between Colombo and GST
Both Colombo and GST sit inside the 9 AM – 5 PM working day between 10:30 AM–5:00 PM IST, which is 9:00 AM–3:30 PM GST. That gives roughly 6 hours and 30 minutes of shared time — the safest window for a live call or meeting.
Business hours overlap
Colombo and GST share 6 hours of working-hours overlap (10:30 AM–5:00 PM IST), so scheduling a live meeting is straightforward.
Colombo is 1 hour 30 minutes behind GST (IST UTC+05:30 → GST UTC+04:00). The shared working window is 10:30 AM–5:00 PM IST. 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 Colombo and GST?
Colombo (IST, UTC+05:30) is 1 hour 30 minutes behind GST (GST, UTC+04:00). The gap is currently -1h 30m.
How do I convert Colombo time to GST time?
Add -1h 30m to Colombo local time. For example, 9:00 AM in Colombo is 7:30 AM in GST.
What time is it in GST right now?
GST uses GST at UTC+04:00. Use the live converter at the top of this page — it updates in real time and already accounts for the -1h 30m offset from Colombo.
What is the best time to call GST from Colombo?
Call between 10:30 AM and 5:00 PM IST — that maps to 9:00 AM–3:30 PM GST and keeps both parties inside the working day.
Which is behind, Colombo or GST?
Colombo is 1 hour 30 minutes behind GST. When it is 12:00 PM in Colombo it is 10:30 AM in GST.
Do Colombo and GST use different time zones?
Colombo (Sri Lanka) uses IST at UTC+05:30, while GST uses GST at UTC+04:00. The IANA identifiers are Asia/Colombo and Asia/Dubai.
Does daylight saving time affect the Colombo–GST difference?
Neither zone observes daylight saving time, so the -1h 30m offset between Colombo and GST is fixed all year.
Which other cities share Colombo's time zone?
IST also covers Mumbai, Delhi, Bangalore, Kolkata, Chennai, Hyderabad, Pune, Ahmedabad and 4 more.
Which countries use IST, Colombo's zone?
IST is used in India, Sri Lanka.
Is there a day difference between Colombo and GST?
Not normally. The -1h 30m gap only pushes the date over the previous day.
What is the time difference between Colombo and GST?
GST is -1h 30m from Colombo.
What timezone is Colombo in?
Colombo operates on Sri Lanka Time (SLST), UTC+5:30. Sharing India's timezone, Colombo is a key South Asian trade and tourism hub.
What timezone is GST in?
GST operates on its local timezone.
What are the business hours in Colombo?
Standard business hours in Colombo are 9:00 AM - 5:00 PM IST.
Which countries use IST (India Standard Time)?
IST is used in India, Sri Lanka.
Does IST observe daylight saving time?
No, IST does not observe daylight saving time and remains at UTC+05:30 year-round.
What are some interesting facts about IST?
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.
Which cities are in the GST timezone?
Major cities in the GST timezone include Dubai, Abu Dhabi, Muscat, Baku, Tbilisi.
What is the UTC offset for GST?
Gulf Standard Time (GST) is at UTC+04:00.
What should I know about the GST timezone?
Dubai uses GST year-round with no daylight saving time. GST is 9 hours ahead of EST and 4 hours ahead of GMT.
When is it midnight in Colombo, what time is it in GST?
When it is 12:00 AM (midnight) in Colombo (IST), it is -1h 30m later in GST (GST).
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