Colombo to MDT
-11h 30mColombo
ISTSOURCEMDT
MDTGreen rows indicate typical business hours (9 AM - 5 PM)
IST and MDT on the World Map
The map below highlights the IST (India Standard Time) and MDT (Mountain Daylight 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.
MDT – Mountain Daylight Time
UTC-06:00Mountain Daylight Time (MDT) is the daylight saving offset in the Mountain Time Zone, 6 hours behind UTC.
- •MDT shares the same offset as CST (UTC-06:00).
- •Arizona does not switch to MDT, remaining on MST.
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.
Time Conversion Guide: Colombo to MDT
Colombo runs on India Standard Time (IST) at UTC+05:30. MDT runs on Mountain Daylight Time (MDT) at UTC-06:00. That puts Colombo 11 hours 30 minutes behind MDT — a difference of -11h 30m at the current offsets.
In practice, when it is 9:00 AM in Colombo it is 9:30 PM in MDT on the previous day. Midnight in Colombo is 12:30 PM in MDT. Neither zone observes daylight saving time, so the offset between them stays constant all year.
Colombo to MDT time conversion table
| Colombo (IST) | MDT (MDT) | Day |
|---|---|---|
| 12:00 AM | 12:30 PM | previous day |
| 6:00 AM | 6:30 PM | previous day |
| 7:00 AM | 7:30 PM | previous day |
| 8:00 AM | 8:30 PM | previous day |
| 9:00 AM | 9:30 PM | previous day |
| 12:00 PM | 12:30 AM | same day |
| 3:00 PM | 3:30 AM | same day |
| 5:00 PM | 5:30 AM | same day |
| 6:00 PM | 6:30 AM | same day |
| 9:00 PM | 9:30 AM | same day |
Why people convert Colombo to MDT time
- Scheduling a call from Colombo to MDT: a 10:00 AM start in Colombo lands at 10:30 PM in MDT the previous day, so you can confirm the slot without doing the arithmetic yourself.
- Handling a -11h 30m gap: Colombo and MDT have no overlap inside a normal 9-to-5 day, so real-time meetings need an early-morning or late-evening slot on one side. 9:00 AM in MDT is 9:30 PM in Colombo.
- Keeping family and friends in sync: knowing that 8:00 PM in Colombo is 8:30 AM in MDT makes it easy to avoid calling at 3 AM.
- Always state the zone abbreviation, not just the hour. "3:00 PM IST" is unambiguous; "3 PM" across a -11h 30m gap is not.
- With a -11h 30m gap there is no shared 9-to-5 window, so alternate the early start: one week Colombo takes the early slot, the next week MDT does.
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 MDT (Mountain Daylight Time)
Mountain Daylight Time (MDT) is observed during summer months in the Mountain Time Zone, except in Arizona which stays on MST year-round. MDT aligns with Central Standard Time (CST) at UTC-06:00.
Best time to call between Colombo and MDT
With a -11h 30m offset there is no overlap inside a normal 9 AM – 5 PM day. MDT opens at 9:00 AM MDT, which is 9:30 PM in Colombo, so real-time calls need an early-morning or late-evening slot on one side.
Business hours overlap
Colombo and MDT have no shared working hours because of the -11h 30m gap. Teams need to alternate early starts or rely on asynchronous handovers.
Colombo is 11 hours 30 minutes behind MDT (IST UTC+05:30 → MDT UTC-06:00). There is no shared 9-to-5 window, so plan around an early or late slot. Remember to re-check around daylight-saving transitions.
🕐 Daylight Saving Time Info
Colombo
Does not observe DST
MDT
☀ Currently in DST
Standard: UTC-07:00 · DST: UTC-06:00
Clocks fall back on Sun, Nov 1, 2026
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 MDT?
Colombo (IST, UTC+05:30) is 11 hours 30 minutes behind MDT (MDT, UTC-06:00). The gap is currently -11h 30m.
How do I convert Colombo time to MDT time?
Add -11h 30m to Colombo local time. For example, 9:00 AM in Colombo is 9:30 PM in MDT (previous day).
What time is it in MDT right now?
MDT uses MDT at UTC-06:00. Use the live converter at the top of this page — it updates in real time and already accounts for the -11h 30m offset from Colombo.
What is the best time to call MDT from Colombo?
There is no shared working-hours window because of the -11h 30m gap. The closest option is 1:00 PM in Colombo, which is 1:30 AM in MDT.
Which is behind, Colombo or MDT?
Colombo is 11 hours 30 minutes behind MDT. When it is 12:00 PM in Colombo it is 12:30 AM in MDT.
Do Colombo and MDT use different time zones?
Colombo (Sri Lanka) uses IST at UTC+05:30, while MDT uses MDT at UTC-06:00. The IANA identifiers are Asia/Colombo and America/Denver.
Does daylight saving time affect the Colombo–MDT difference?
Neither zone observes daylight saving time, so the -11h 30m offset between Colombo and MDT 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 MDT?
Not normally. The -11h 30m gap only pushes the date over the previous day.
What is the time difference between Colombo and MDT?
MDT is -11h 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 MDT in?
MDT 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 MDT timezone?
Major cities in the MDT timezone include Denver, Calgary, Edmonton, Salt Lake City, Boise.
What is the UTC offset for MDT?
Mountain Daylight Time (MDT) is at UTC-06:00. During daylight saving time, it shifts to MST.
What should I know about the MDT timezone?
MDT shares the same offset as CST (UTC-06:00). Arizona does not switch to MDT, remaining on MST.
When is it midnight in Colombo, what time is it in MDT?
When it is 12:00 AM (midnight) in Colombo (IST), it is -11h 30m later in MDT (MDT).
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