Aṣṭakūṭa ('eight-fold') is the classical 8-factor compatibility computation performed between two charts before marriage. Each of the eight kūṭas tests a different dimension of alignment between the two charts (primarily based on the Moon's nakṣatra-position in each).
The eight factors and their point-weights: varṇa (1) tests social-elemental class; vaśya (2) tests dominant-temperament; tārā (3) tests health-trajectory based on nakṣatra-distance; yoni (4) tests sexual-temperamental compatibility; graha-maitrī (5) tests friendship between the Moon-lords; gaṇa (6) tests temperament-class (deva-gaṇa, manuṣya-gaṇa, rākṣasa-gaṇa); bhakūṭa (7) tests bhāva-level compatibility from the Moon; nāḍī (8) tests genetic-line compatibility.
The standard classical threshold is 18+ out of 36 guṇas (so 50%+); a score of 24+ is generally considered good; 28+ is very good. However, two specific doṣas — nāḍī-doṣa and bhakūṭa-doṣa — are weighted heavily even if the overall sum is high, and the classical tradition has detailed bhaṅga rules for when these doṣas can be considered cancelled.
Ethical discipline: aṣṭakūṭa is ONE input among many for marriage-evaluation. The classical tradition is unanimous that aṣṭakūṭa alone is insufficient — the full chart-pair analysis (7th-bhāva, navāṃśa, dāra-kāraka, Venus-position, upapada) must also be considered. Aṣṭakūṭa is a useful filter, not a verdict-engine.