EDT to IST Converter

Curated Call Slots

Hour-by-Hour Table

See also EST to IST for the winter offset focus.

The EDT to IST Formula

Nothing saved yet. Tap "Save Slot" to remember up to six time pairings.

How to Convert EDT to IST

1. Read the live NYC clock - is it on EDT (summer) or EST (winter)?
2. Add 9h 30m for EDT, or 10h 30m for EST. The result is the matching Mumbai hour.
3. Check the day badge - early morning IST is often the previous day in NYC.
4. Use the picker to lock a specific hour and read off the matching Mumbai time.
5. Save up to six recurring slots to the local history.

A Short History of EDT and IST

Eastern Standard Time (UTC-5) and Eastern Daylight Time (UTC-4) anchor the United States Atlantic seaboard from Maine to Florida and the Great Lakes belt: New York, Boston, Washington DC, Philadelphia, Atlanta, Miami, Detroit, Pittsburgh, Cleveland, Buffalo, and Toronto on the Canadian side. The zone was formalised by the Standard Time Act of 1918, signed by Woodrow Wilson on 19 March of that year. Before 1918, even Manhattan ran several minutes off Brooklyn time, and the New York Central Railroad operated five different railway clocks on a single platform at Grand Central.

New York City - the unofficial capital of the Eastern time zone - sits at 40.71 degrees north, 74.01 degrees west, a few minutes east of the 75 degrees west meridian that defines the zone's central solar offset. The New York Stock Exchange at 11 Wall Street rings its opening bell at 9:30 AM ET and the closing bell at 4:00 PM ET. The NYSE's 9:30 AM ET opening corresponds to 7:00 PM IST in summer (EDT) and 8:00 PM IST in winter (EST), which is precisely why Mumbai-based equities trading desks at Edelweiss, Motilal Oswal, and Kotak run a dedicated US-Equities Night Shift covering the full NYSE session - 7:00 PM to 1:30 AM IST in summer.

Indian Standard Time was established at the Madras (now Chennai) Observatory in 1906 by the British colonial administration. The 82.5 degrees east meridian, which runs through Mirzapur in Uttar Pradesh, gives the offset UTC+5:30. Before 1906 the major Indian cities ran on three separate civil times: Bombay Time (UTC+4:51, anchored to the Bombay Observatory at Colaba), Madras Time (UTC+5:21), and Calcutta Time (UTC+5:53). The Great Indian Peninsular Railway begged the colonial administration to unify these because of repeated timetable failures during the monsoon when telegraph signals slowed.

The New York-India software services and finance corridor scaled rapidly through the 1990s and 2000s. Goldman Sachs, Morgan Stanley, JP Morgan Chase, Citi, Bank of America, BNY Mellon, BlackRock, Bloomberg, Reuters, and S&P Global all maintain large Indian operations centres - mostly in Bengaluru, Hyderabad, Mumbai, Pune, and Gurugram - because of the natural NYC-evening to India-morning handoff. Companies like TCS, Infosys, Wipro, HCL, Cognizant, Tech Mahindra, Mphasis, and L&T Technology Services have hundreds of thousands of engineers organised into ‘US East shift’ rotations that match 9:30 AM EDT to 5:00 PM EDT = 7:00 PM IST to 2:30 AM IST.

Daylight Saving Time, the source of the EST-versus-EDT distinction, was popularised by the New Zealand entomologist George Hudson in 1895 and by the English builder William Willett in 1907. Germany adopted DST first on 30 April 1916 to save coal during the First World War. The United States followed in 1918, repealed it in 1919, briefly reintroduced ‘War Time’ in 1942, and only made it permanent under the Uniform Time Act of 1966. The 2007 Energy Policy Act, signed by George W. Bush on 8 August 2005, extended DST to start on the second Sunday of March and end on the first Sunday of November - the schedule still in use in 2026.

India never adopted DST. The Indian government considered it briefly during the 1962 Sino-Indian war and again during the 1971 Bangladesh war but concluded that India's near-equatorial latitude provides almost the same daylight every day. The Indian Institute of Astrophysics now maintains the IST signal using a network of caesium-fountain atomic clocks at the National Physical Laboratory (NPL) in New Delhi, traceable to international atomic time via BIPM in Paris. The Sunday Times Magazine 1959 article on Indian timekeeping noted that the Madras Observatory's decision to centre IST at 82.5 degrees east, rather than the round-number 75 or 90, was the only way to give a single coherent civil time to the subcontinent.

Modern timezone software, including the dual clocks on this page, draws on the IANA Time Zone Database (TZDB), founded by Arthur David Olson at the National Institutes of Health in 1986 and now maintained collaboratively at iana.org/time-zones. The identifier America/New_York encodes every DST rule change going back to 1880 including the 1918 Standard Time Act, the 1942-1945 War Time period, the 1966 Uniform Time Act, the 1986 amendments, and the 2007 Energy Policy Act extensions. Asia/Kolkata encodes the 1906 Madras Observatory standardisation, the 1947 Indian Standard Time Act, and the brief 1942-1945 war-related half-hour shifts. Every Linux, macOS, iOS, Android, and modern browser ships TZDB.