Calculate the position of the Vertex and Anti-Vertex in your birth chart. These sensitive points relate to fated encounters and karmic connections.
Find your Ascendant sign and degree from your birth chart, then use the table below to convert it to total longitude.
Enter your geographical birth latitude. Use positive numbers for the Northern Hemisphere and negative for the Southern Hemisphere.
Your Vertex / Anti-Vertex
function formatLongitude(longitude) {
var signs = ["Aries", "Taurus", "Gemini", "Cancer", "Leo", "Virgo", "Libra", "Scorpio", "Sagittarius", "Capricorn", "Aquarius", "Pisces"];
if (longitude = 360) {
longitude = (longitude % 360 + 360) % 360;
}
var signIndex = Math.floor(longitude / 30);
var degreeInSign = longitude % 30;
var degrees = Math.floor(degreeInSign);
var minutes = Math.floor((degreeInSign – degrees) * 60);
var sign = signs[signIndex];
return degrees + "° " + minutes + "' " + sign;
}
function calculateVertex() {
var ascLon = parseFloat(document.getElementById('ascendantLongitude').value);
var lat = parseFloat(document.getElementById('birthLatitude').value);
var resultContainer = document.getElementById('result-container');
var vertexResultEl = document.getElementById('vertexResult');
var antiVertexResultEl = document.getElementById('antiVertexResult');
if (isNaN(ascLon) || isNaN(lat) || ascLon = 360 || lat 90) {
resultContainer.style.display = 'block';
vertexResultEl.innerHTML = "Please enter valid inputs. Ascendant Longitude must be 0-359.9, and Latitude must be -90 to 90.";
antiVertexResultEl.innerHTML = "";
return;
}
// Constants
var obliquity = 23.439281; // Obliquity of the Ecliptic in degrees
// Convert to Radians
var ascLonRad = ascLon * Math.PI / 180;
var latRad = lat * Math.PI / 180;
var oblRad = obliquity * Math.PI / 180;
// 1. Calculate Right Ascension of the Ascendant (alpha_asc)
// This is the point on the celestial equator corresponding to the Ascendant's longitude
var alpha_asc = Math.atan2(Math.sin(ascLonRad) * Math.cos(oblRad), Math.cos(ascLonRad));
// 2. Calculate Longitude of the Anti-Vertex (East Point on the Ecliptic)
// This uses spherical trigonometry to find the intersection of the Prime Vertical and the Ecliptic in the east.
var num = -Math.cos(alpha_asc);
var den = Math.sin(alpha_asc) * Math.cos(oblRad) + Math.tan(latRad) * Math.sin(oblRad);
var antiVertexRad = Math.atan2(num, den);
// 3. Convert Anti-Vertex from radians to degrees and normalize to 0-360 range
var antiVertexLon = antiVertexRad * 180 / Math.PI;
antiVertexLon = (antiVertexLon + 360) % 360;
// 4. Calculate Vertex Longitude (it's always 180 degrees opposite the Anti-Vertex)
var vertexLon = (antiVertexLon + 180) % 360;
// 5. Format output into Sign, Degree, and Minute
var vertexOutput = formatLongitude(vertexLon);
var antiVertexOutput = formatLongitude(antiVertexLon);
// Display results
resultContainer.style.display = 'block';
vertexResultEl.innerHTML = "Vertex: " + vertexOutput;
antiVertexResultEl.innerHTML = "Anti-Vertex: " + antiVertexOutput;
}
What is the Vertex in Astrology?
The Vertex (Vx) is not a planet or asteroid, but a calculated, sensitive point in the birth chart. It represents the intersection of the ecliptic (the Sun's apparent path) and the prime vertical (the great circle passing through the east point, zenith, west point, and nadir). In simpler terms, it's the point that was due west at the moment of your birth.
Astrologically, the Vertex is often called the "third angle" of the chart, alongside the Ascendant/Descendant and Midheaven/IC axes. It is strongly associated with fated encounters, karmic connections, and significant turning points in life that feel beyond our conscious control. When the Vertex is activated by transits or in synastry (chart comparison), it can bring people and events into our lives that have a profound and destined quality.
The point exactly opposite the Vertex is the Anti-Vertex (AVx). While the Vertex represents the fated qualities we encounter in others, the Anti-Vertex represents the qualities within ourselves that attract these experiences.
How to Use the Vertex Calculator
To find your Vertex, you need two key pieces of information from your birth chart:
Your Ascendant Longitude: Your Ascendant, or Rising Sign, is given as a sign and degree (e.g., 15° Leo). You must convert this to a single number from 0-359. Use the table below to find the starting degree for your Ascendant sign and add the degrees of your Ascendant to it.
Your Birth Latitude: The geographical latitude of your birthplace. Use a positive number for locations in the Northern Hemisphere (e.g., 40.7 for New York) and a negative number for the Southern Hemisphere (e.g., -33.8 for Sydney).
Let's say a person was born in Los Angeles, USA and their birth chart shows an Ascendant of 25° Scorpio.
Ascendant Longitude: Scorpio starts at 210°. So, 210 + 25 = 235°.
Birth Latitude: The latitude of Los Angeles is approximately 34.05° N.
Entering 235 for Ascendant Longitude and 34.05 for Birth Latitude into the calculator will yield a Vertex in early Aries and an Anti-Vertex in early Libra.
Frequently Asked Questions (FAQ)
Q: Why is the Vertex always on the right side of the chart?
A: By definition, the Vertex is the western intersection of two astronomical planes. The western half of a standard astrological chart corresponds to houses 5, 6, 7, and 8. Therefore, the Vertex will always fall within one of these four houses.
Q: What's the difference between the Vertex and the Descendant?
A: The Descendant (7th house cusp) represents the qualities we consciously seek in a partner and one-to-one relationships. The Vertex represents fated, karmic, or "electric" encounters that we don't consciously seek but which have a powerful impact on our life's direction. It's the difference between choice (Descendant) and destiny (Vertex).
Q: How accurate is this calculator?
A: This calculator uses standard spherical trigonometry formulas used in astrological software. Its accuracy is entirely dependent on the accuracy of the Ascendant longitude and birth latitude you provide. An error in your birth time can shift the Ascendant, which will in turn shift the calculated Vertex position.