There is no overlap between 09:00–18:00 working days in these two places.
How many hours is IST ahead of EST?
As abbreviations, EST is always 10.5 hours behind of IST: IST is UTC+5:30 and EST is UTC−5. To convert, subtract 10.5 hours.
Check which label you actually need: EST (Eastern Time is on EDT today). A time written with an abbreviation that is not in use is usually meant as the local time, so convert between the places instead: right now EST is 9.5 hours behind of IST.
When the IST to EST time difference changes
For most of the year EST is 9.5 hours behind of IST. From 1 November to 31 December 2026, EST is 10.5 hours behind of IST instead, because the two places change their clocks on different dates. Meetings booked by the usual gap land an hour off in those weeks.
Dates
EST vs IST
Length
8 March 2026 to 31 October 2026
9.5 hours behind
238 days
1 November 2026 to 31 December 2026
10.5 hours behind
61 days
1 January 2027 to 13 March 2027
10.5 hours behind
72 days
14 March 2027 to 6 November 2027
9.5 hours behind
238 days
7 November 2027 to 31 December 2027
10.5 hours behind
55 days
Calling hours for IST and EST
When EST is 9.5 hours behind of IST: no shared 09:00 to 17:00 hours; try 17:00 in IST (07:30 in EST).
When EST is 10.5 hours behind of IST: no shared 09:00 to 17:00 hours; try 18:00 in IST (07:30 in EST).
A 10-hour 30-minute gap splits Mumbai from New York in January. Noon in Mumbai, 01:30 the same morning on the US East Coast. By July the gap shrinks to 9 hours 30 minutes: noon in Mumbai, 02:30 in New York. The half-hour offset on the Indian side never moves. The US side does.
From 15 January 2026: New York is 10.5 hours behind IST. 14:00 IST = 03:30 EST.
From 15 July 2026: New York is 9.5 hours behind IST. 14:00 IST = 04:30 EDT.
IST vs EST vs EDT
Time zone
Abbreviation
UTC offset
When used
India Standard Time
IST
UTC+5:30
All year
Eastern Standard Time
EST
UTC-5
November, March
Eastern Daylight Time
EDT
UTC-4
March, November
The US switches to EDT on the second Sunday of March and back to EST on the first Sunday of November. Check the current date before converting.
IST to EST time conversion table
IST
EST (winter)
EDT (summer)
06:00
19:30 previous day
20:30 previous day
12:00
01:30 same day
02:30 same day
17:30
07:00 same day
08:00 same day
20:00
09:30 same day
10:30 same day
What are the best hours for an IST to EST meeting?
The best time for a meeting between India and the US East Coast is 07:00-09:30 EST / 17:30-20:00 IST.
This window works because:
India office hours typically run 09:30-18:00 IST.
US East Coast office hours typically run 09:00-17:00 EST/EDT.
17:30-20:00 IST falls at the end of the Indian workday and the start of the US workday.
Avoid scheduling outside 07:00-09:30 EST. Before 07:00 EST, it is too early for US participants. After 20:00 IST, it is too late for Indian participants.
Who should do something different: If you work in a US company with a largely Indian team, schedule meetings at 08:30-09:00 EST (18:30-19:30 IST). This gives the Indian team the last hour of their day and the US team the first hour of theirs. If you work in an Indian company with US clients, push meetings to 07:00-08:00 EST (17:30-18:30 IST) so the Indian team can finish on time.
Frequently asked questions about IST and EST time
Why is the conversion 10 hours 30 minutes and not a round number?
IST is UTC+5:30, based on the 82.5°E meridian. EST is UTC-5. The difference is 10.5 hours. No rounding.
Does India ever change its clocks?
No. India has never observed daylight saving time at a national level. The offset stays UTC+5:30 all year.
Is the conversion the same for New York, Toronto, and Miami?
Yes. All locations on the US East Coast use EST in winter and EDT in summer. The conversion is identical.
What if I see "IST" and it means Irish Standard Time?
Irish Standard Time (UTC+1) is a different zone. The abbreviation is the same but the offset is not. Always check whether "IST" refers to India or Ireland. See the IST abbreviation meanings page for the full list.
How many hours ahead is EST of IST?
EST (UTC−5) is 10.5 hours behind of IST (UTC+5:30).
Does the time difference between IST and EST change?
Yes. It is usually 9.5 hours behind, but changes when one side moves its clocks: 10.5 hours behind from 1 November to 31 December 2026; 10.5 hours behind from 1 January to 13 March 2027.