How to Calculate the Part of Fortune

POFThe Part of Fortune is one of the Arabic parts, also known as a Lot. The Arabic parts are imaginary points in the horoscope, calculated mathematically to show the point of integration between various other planets and points in the chart. The Part of Fortune, sometimes just called Fortuna, shows the point of integration between the Sun, Moon and Ascendant, and is symbolised with a cross inside a circle.

There are many different Parts and they’re all calculated by adding the longitude of a particular planet to the longitude of the Ascendant, and then subtracting the longitude of the Sun. For the Part of Fortune you use the Moon to do the calculation, but the method is different for day and night births:

Day Births: Ascendant + Moon – Sun = ⊗

Night Births: Ascendant + Sun – Moon = ⊗

To do the calculation the first thing you need is an accurate birth time. Without this you can’t know the precise position of the Ascendant or the Moon.

Next, you need to convert the positions of the Sun, Moon and Ascendant into degrees within a full circle. Use this table to work out the longitudes of the Sun, Moon and Ascendant:

0° Aries = 0° 0° Libra = 180°
0° Taurus = 30° 0° Scorpio = 210°
0° Gemini = 60° 0° Sagittarius = 240°
0° Cancer = 90° 0° Capricorn = 270°
0° Leo = 120° 0° Aquarius = 300°
0° Virgo = 150° 0° Pisces = 330°

For example (using the details of my chart):

Ascendant: 10° Aquarius = 310

Moon: 12° Leo = 132

Sun: 5° Virgo = 155

Example Calculation for Part of Fortune

I was born just before 7 pm so this might look like a night birth, but it was August so the sun hadn’t set yet. All day births give you a Sun placement above the horizon in houses 7 – 12. The Sun is in my 7th house, above the horizon, so it’s a day birth. So the calculation is Ascendant + Moon – Sun as follows:

310 + 132 = 442 – 155 = 287

Convert the result back into the degree of the correct sign:

287 = 17° Capricorn

When you do this calculation, if the result of adding the Asc to the Moon equals less than the Sun, add 360 before deducting the Sun.

In night births, the Sun will always be found in the lower half of the chart in houses 1 – 6, under the horizon. Using the same numbers as above, let’s imagine I was born at night, so now the calculation is Ascendant + Sun – Moon as follows:

310 + 155 = 465 – 132 = 333

Convert the result back into the degree of the correct sign:

333 = 3° Pisces

It’s useful to remember that “as the Moon is to the Sun, so is the Part of Fortune to the Ascendant.” In other words, the Part of Fortune should be at the same distance from the Ascendant as the Moon is from the Sun. So if the Sun and the Moon are conjunct, for example, the Part of Fortune should be conjunct the Ascendant.

Symbolically speaking, the Part of Fortune represents the sunrise of the Moon – the soul incarnate. Find out more about how the Part of Fortune works and what it represents here: Guidelines for Interpreting the Part of Fortune

Back to Part of Fortune Page


4 thoughts on “How to Calculate the Part of Fortune

  1. Hey, you had the best way to calculate the part of fortune, I felt like I conquered the world when I actually calculated it right after failing to understand from the theosophical societies directions for it just confused me. I am not as good at some forms of math, but the directions that the author gave is kind of confusing, using direction like forwards and backwards (instead of clockwise and counter clockwise). Do you think you can help me with undertsanding how to calculate the parts of the different planets if I give you their directions? (Part of saturn, part of sun, part of mercury, part of jupiter, part of venus ect.)?



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