Calculator - Upapada Lagna

If the 12th lord is in the 12th house, the UL is taken as the 10th house from the 12th (some traditions use the 2nd house from the 12th—consulting a Vedic expert is recommended for this edge case).

Upapada Lagna is located in the Dwikendra (two-centered) structure: it is the arudha (image or reflection) of the 12th house. The 12th house traditionally governs losses, bed pleasures, and foreign travel, but in Jaimini, its arudha reveals the nature of one’s spouse and the marriage itself. Upapada Lagna Calculator

Better formulation (standard Jyotisha):

This post covers the essential components of a used in Vedic Astrology to determine the nature, longevity, and characteristics of marriage and a spouse. What is Upapada Lagna (UL)? If the 12th lord is in the 12th

From the position of that 12th lord, count the same number of houses forward. Better formulation (standard Jyotisha): This post covers the