Vertex calculator: find your Vertex sign

The Vertex is a calculated point in the western half of the chart. It is where the ecliptic, the path of the Sun and planets, crosses the prime vertical: the great circle that runs from due east through the point straight overhead to due west. Its opposite is the Antivertex, in the east. Together they form a third axis beside the horizon and the meridian.

Many modern astrologers read the Vertex as a point of meetings that feel destined and that change something. It has no ancient tradition behind it. It entered astrology in the 20th century and is treated as a minor, sensitive point, a tradition to think with and not a verdict.

Because it lies in the west, the Vertex falls in the western half of the chart. In the middle latitudes that means the 5th to the 8th house, most often the 7th or close to it; near the equator the range widens to the 4th through the 9th. Astrologers read the house as the area of life where the meetings come: a Vertex in the 5th through romance or creative work, in the 7th through partners, in the 11th through friends.

Which house it is depends on the house system, since the point itself does not move. The calculator shows all four systems, and says so when Placidus and Koch cannot be drawn near the polar circles.

A planet within about 5 degrees of the Vertex, or of the Antivertex, is read as the one that colors those meetings. Venus is read as affection and attraction, Mars as sparks and conflict, Saturn as serious, lasting or delayed contact, Jupiter as generous people and opportunities, the Moon as familiarity and care.

The calculator lists the planets within 5 degrees of the Vertex. If it says none, the Vertex has no close companion, which is common: the point simply speaks for itself through its sign and house.

The Antivertex is the point opposite the Vertex, 180 degrees away, in the eastern half of the chart. Where the Vertex is read as what comes to you, the Antivertex is read as what you bring to the meeting: your own part in it. The two work as a pair, the way the ascendant and the descendant do.

The calculator shows the Antivertex sign and degree next to the Vertex. If your Vertex is in Libra, the Antivertex is in Aries, and the two signs are read together.

The Vertex turns once around the zodiac every 24 hours, as the Ascendant does, so it changes sign about every two hours. Two people born on the same day in the same city can have it in different signs, and a birth date alone says nothing about it. That is why the calculator does not guess at noon: without a time it shows no houses at all.

A birth certificate or hospital record is the best source for the time, then a parent's memory of the hour. A few minutes of error rarely changes the sign, but close to a sign change ten or fifteen minutes can. The rising sign calculator needs the same time.

The Vertex is the Ascendant formula run for the co-latitude, 90 degrees minus your latitude, at the opposite sidereal time, the RAMC plus 180 degrees, and then taken on the western side of the meridian. The calculator uses the true obliquity of the ecliptic and the apparent sidereal time of your birth moment.

We check the result against the Swiss Ephemeris, the standard reference, for charts in both hemispheres, and it agrees to within a few arcseconds. Everything is computed in your browser, and the tool is free. For the Vertex among all your planets and aspects, open the birth chart calculator.

The Vertex is often mixed up with the descendant because both sit in the west and both are linked to other people. They are different points: the descendant is the Ascendant plus 180 degrees and starts the 7th house, while the Vertex is on the prime vertical and can lie in any of several houses. The descendant describes the partners you choose, the Vertex the meetings that seem to find you.

If you want the 7th house itself, use the descendant calculator; for the planet of attraction, the Venus sign calculator.