What is the IST to EST Converter?
This tool converts a time given in India Standard Time (IST, UTC+5:30) to United States Eastern Standard Time (EST, UTC−5:00). The two zones differ by a fixed 10 hours and 30 minutes, so EST is always IST minus 10h 30m. Note this uses standard time (EST); during US daylight saving (EDT, UTC−4) the gap shrinks to 9h 30m.
How to use it
Enter the IST hour using a 24-hour clock (0–23) and the minute (0–59). The calculator returns the equivalent Eastern time, the EST hour and minute separately, and a day offset that tells you whether the result lands on the previous calendar day.
The formula explained
We convert the IST time to minutes since midnight, subtract 630 minutes (10×60 + 30), then wrap the result into the 0–1439 range with modulo 1440. If the subtraction goes below zero, the EST time falls on the previous day, so the day offset is −1.
$$\text{EST} = \Big(\,60\cdot\text{IST Hour} + \text{IST Minute} - 630\,\Big) \bmod 1440$$
Worked example
For 14:00 IST: minutes = 840. \(840 - 630 = 210\) minutes = 3:30. Since \(210 \geq 0\), the day offset is 0 — so 2:00 PM in India is 3:30 AM the same day in New York.
FAQ
Is EST the same as EDT? No. EST is standard time (winter); EDT is daylight time (summer) and is one hour ahead of EST.
Why 10.5 hours? IST is UTC+5:30 and EST is UTC−5:00, a difference of 10 hours 30 minutes.
What does the day offset mean? A −1 offset means the converted Eastern time is on the previous calendar day relative to the IST date.
