If you were born during daylight saving time, one specific data-entry mistake can quietly shift your entire chart, and it is common enough to be worth calling out directly.
The mistake: using standard time zone instead of the DST offset
Most people know their birth city’s standard time zone (like Eastern Time, UTC-5), but during daylight saving periods, clocks are set an hour ahead. A birth certificate or hospital record showing “2:15 PM” during DST means the actual standard-time equivalent is 1:15 PM, a full hour earlier. A calculator that applies the standard offset to a DST-recorded time will compute the wrong sidereal time, and every downstream calculation shifts with it.
Why this matters more than it sounds
An hour of error moves the lagna (which changes roughly every two hours) meaningfully, and can shift finer details in nakshatra pada and dasha timing too. For a birth close to a DST transition (the specific hour when clocks change), this becomes even trickier, since that hour may occur twice or not at all on the transition date.
Historical DST rules also matter
Some countries have added, removed, or changed their DST rules entirely over the decades. A tool needs to apply the DST rule that was actually in effect on the specific birth date, not today’s rule for that location.
Make sure your tool handles this correctly
A reliable kundli tool should account for DST automatically based on the birth date and location, rather than asking you to do the conversion yourself.
This information is descriptive.