Free Hyleg Calculator

The hyleg is the planet or chart point selected from a small set of traditional vitality candidates: the Sun, the Moon, the Ascendant, the Lot of Fortune, and the prenatal syzygy (the New or Full Moon before birth). Ptolemy, Dorotheus, Valens, and Perso-Arabic authors preserve related length-of-life doctrines, but the exact rules vary by author. This calculator uses a visible modern rule set instead of claiming one uncontested ancient reconstruction.

The word hylegis the later Persian-Arabic and Latin name for the traditional "giver of life" or releaser. On this page that label is historical shorthand. It does not mean the calculator measures life expectancy, medical health, or a death date.

Modern astrologers don't compute hylegs much. The technique was tied to length-of-life work, which fell out of practice in the twentieth century and has only partially returned through the Hellenistic revival. But the hyleg can still be useful as symbolic chart testimony. Read it as a traditional vitality anchor to compare with the Ascendant, the sect light, the chart ruler, and the broader dignity picture.

The Sun. In day births, the Sun is checked first. When it is selected, read solar topics like agency, visibility, leadership, and bodily presence as especially relevant vitality testimony.

The Moon. In night births, the Moon is checked first. When it is selected, read lunar topics like cycles, care, appetite, sleep, and physical maintenance as especially relevant vitality testimony.

The Ascendant. When neither luminary qualifies, the Ascendant can take over in this rule set. It keeps the reading grounded in embodiment, appearance, temperament, and the way the chart meets the world.

The Lot of Fortune. A calculated point, the projection of the Sun-Moon arc onto the Ascendant (sect-flipped at night). When it qualifies as hyleg, compare Fortune's sign, house, and ruler with the material circumstances of the chart. See the Lot of Fortune calculator for the full computation.

The Prenatal Syzygy. The least-used candidate in this tool: the New or Full Moon immediately before your birth. When it qualifies, the reading often centers on the natal lunation, inherited context, and the chart's pre-birth sky.

Classical astrologers used the hyleg in length-of-life calculations with a technique that combined the alcocoden's planetary years and primary directions to anaretic (destroying) degrees. Bonatti's version is the most-cited; Lilly transmitted it into English in the seventeenth century.

Modern traditional astrologers debate these techniques heavily. The Seven Stars overview documents the diversity of rules, the later medieval dependence on planetary years, and the risk of retrofitting missed predictions. The technique remains valuable as classical history and as symbolic vitality testimony. It does not give you a death date.

If you wanted a prediction tool, this is not one. If you wanted a transparent traditional vitality marker to compare with the rest of the chart, that is the intended use.

Classical authorities: Ptolemy Tetrabiblos III.10 (hylegiacal places), Dorotheus of Sidon Carmen Astrologicum III, Vettius Valens Anthology III, Perso-Arabic length-of-life authors, Guido Bonatti Liber Astronomiae III, and William Lilly Christian Astrology.

Modern reception: Bernadette Brady The Hyleg and Alcoccoden, Robert Schmidt Definitions and Foundations, Skyscript's hyleg glossary, and Seven Stars Astrology's overview of traditional length-of-life techniques.

Computational defaults: computed from the same natal chart service used by the rest of the public tools. Whole Sign houses by default. Lot of Fortune sect-corrected. Dignity scoring uses Egyptian Bounds and Dorothean triplicities. Tiebreaking applies sect priority first, then self-dignity, then angularity. For the dignity layer alone, see the essential dignities calculator.