⊗ Free Part of Fortune Calculator — Day and Night Formula
Umbriel's free Part of Fortune calculator finds your Lot of Fortune from your birth date, time and place, using the day or night formula according to whether you were born with the Sun above or below the horizon. No account, no email. That reversal is the single most common thing other calculators get wrong.
- What you'll needBirth date, exact time and place
- What you getYour Part of Fortune's sign, exact degree and house — calculated with the correct day or night formula — plus the full canon of traditional lots
- CostFree — no account required
Runs in your browser. Nothing to install, nothing to set up.
What the Part of Fortune actually is
The Part of Fortune, or Lot of Fortune, is the oldest and best known of the Arabic Parts — sensitive points worked out by arithmetic rather than observed in the sky. Fortune is measured from the Ascendant by the distance between the Sun and the Moon, which is why it carries something of the relationship between the two lights and the horizon at once.
⚠️ And it flips by sect. For a day birth — the Sun above the horizon — the lot is Ascendant + Moon − Sun. For a night birth the formula reverses to Ascendant + Sun − Moon. This is not an optional refinement; it is how the tradition defines it, and skipping it puts a night chart's Fortune in the wrong place, often by a long way. A surprising number of calculators use the day formula for everyone. Umbriel checks whether the Sun was above or below the horizon and uses the right one.
It is traditionally read for wellbeing in a broad, embodied sense — the body, livelihood, the place where things come together with less effort than they should. Because it is built from the Ascendant it needs an accurate birth time, and because it is arithmetic rather than a body it has no orbit, no speed and no retrograde: it is a point the chart implies rather than a thing that was there.
What's in your result
- Sign, exact degree and houseYour Part of Fortune placed properly in the chart rather than quoted as a bare degree.
- The formula actually usedDay or night, named on the page, so you can check it against any other source.
- Your sectWhether you were born by day or by night — which decides the formula and much else in traditional astrology.
- Aspects to FortuneContacts with exact orbs, since a lot can be aspected like any point.
- The full canon of lotsSpirit, Eros, Necessity, Courage, Victory, Nemesis and the rest of the traditional set, all with the same sect handling.
- Fortune in the wheelDrawn on the chart, not listed off to one side.
Common questions
What is the Part of Fortune?
An Arabic Part — a point calculated from your Ascendant, Sun and Moon rather than observed. It is traditionally associated with the body, livelihood and a kind of practical wellbeing, and it is the most widely used of the lots by a wide margin.
What is the day and night formula for the Part of Fortune?
By day it is Ascendant + Moon − Sun; by night it reverses to Ascendant + Sun − Moon. Sect — whether the Sun was above or below the horizon at birth — decides which applies. Umbriel determines your sect and uses the correct formula.
Why is my Part of Fortune different on another website?
Nearly always the sect reversal. Some calculators apply the day formula to every chart, which puts every night birth's Fortune in the wrong place. Check whether the other site says which formula it used — if it does not say, that is usually the answer.
Do I need a birth time for the Part of Fortune?
Yes. It is measured from the Ascendant, which moves a degree every four minutes, so without an accurate time the result is not meaningful.
Is the Part of Fortune calculator free?
Yes — Fortune and the full canon of traditional lots, with correct sect handling, and no account or email.
Go deeper
Every one of these is a page in its own right, written out one at a time.
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Umbriel offers every system here as a set of prompts to think with, never as a statement of fact about who you are. Take what's useful, leave the rest.