Jaimini longevity is simpler than Parashara's detailed calculations. It uses three pairs of sign modalities (moveable, fixed, dual) to arrive at a verdict.
Pair 1: Lagna sign modality vs 8th sign modality.
Pair 2: AK sign modality vs 8th lord sign modality.
Pair 3: AK sign modality vs Lagna sign modality.
Each pair yields a verdict (using a matrix): SHORT (30-60 years), MEDIUM (60-90 years), or LONG (90+ years). The three verdicts are averaged or weighed to arrive at an overall classification.
Adjustment: If Lagna lord is strong and in a Kendra, add years. If AK is weak or combust, subtract years. If Jupiter is in the Lagna, the native likely exceeds the base prediction.
Controversy: This method is empirical. Some astrologers swear by it; others find it inaccurate and prefer Parashara's Shadbala-based method. The lesson presents both schools and encourages you to test the method on your own charts.
Kakshya Hrasa (reduction) and Kakshya Vriddhi (promotion): Special rules where the 8th lord's sign modality overrides the base verdict in certain combinations, effectively promoting or reducing longevity. These are taught as advanced refinements.
The calculator provides the three-pair matrix and adjustment factors. You will predict lifespan for sample charts and compare predictions to family longevity patterns (when known).
The method. Three pairs are compared by sign modality: the lagna and the 8th house, their lords, and a third pair drawn from the Moon or the Atmakaraka depending on the authority followed. Each comparison yields short, medium or long life, and the majority verdict gives the band.
Where the authorities differ. The composition of the third pair is genuinely disputed in the classical literature. Different commentators specify different pairs, and the choice can change the resulting band. A practitioner should know which version they are applying and that alternatives exist.
The dependence on the lagna. Because two of the three pairs involve the ascendant, an inaccurate birth time can shift the entire verdict. Longevity work therefore demands a rectified chart more than almost any other technique in the system.
The ethical boundary. The method yields a broad band, not a date, and even the band is uncertain given the disputes above. Do not convert a longevity band into a predicted age of death, and do not raise the subject with a client who has not asked. The technique's classical purpose was to weight other predictions, not to forecast mortality.