About this calculator
Your Lagna (Ascendant) is the zodiac sign rising on the eastern horizon at your birth. It changes every ~2 hours, which makes it the most time-sensitive point on the chart and the anchor of your entire birth chart (Kundali).
Vedic background
Classical texts like Brihat Parashara Hora Shastra treat the Lagna (tanu bhava) as the most important house — literally 'the body' of the chart. Where the Sun is the soul and the Moon is the mind, the Lagna is the vessel that holds both. Since the Ascendant rotates through all 12 signs in 24 hours, twins born minutes apart can have different Lagnas and dramatically different charts.
