What Is the Part of Fortune?
The Part of Fortune is not a planet. It is a calculated point — the Ascendant plus the Moon minus the Sun in a day chart, and the Ascendant plus the Sun minus the Moon in a night chart.
A point, not a planet
Nothing orbits where your Part of Fortune sits. It is a distance measured out from your Ascendant using the gap between your Sun and your Moon, and then dropped back onto the zodiac. That is why this calculation is exact in a way most are not: given a correct Ascendant, Sun and Moon, the arithmetic cannot drift.
Why it is called a Lot
In Hellenistic astrology, points built by this kind of arithmetic were called lots — or, in the later Arabic-language tradition that carried them forward, parts. Dozens were in use. The Lot of Fortune is the one that survived into modern practice, and the Lot of Fortune is still the only one most software computes by default. Traditionally it concerns the body, livelihood and circumstance: the practical, embodied side of a life rather than its intentions.
Why Day and Night Charts Give Different Answers
The two formulas
There is not one Part of Fortune formula. There are two, and they are mirror images of each other about the Ascendant. A day chart uses Ascendant + Moon − Sun. A night chart uses Ascendant + Sun − Moon. Swapping them does not nudge the result a degree or two — it throws the point most of the way across the chart.
“Day” means the Sun is above the horizon
This is the part that trips up calculators and readers alike. A day chart is not a birth that happened during working hours. It is a birth at which the Sun stood above the horizon — which depends on the date, the latitude and the exact minute, not on the clock. A birth at 05:30 in April is a night chart in Los Angeles. A birth at 23:00 in June is a day chart in northern Norway.
What goes wrong when a calculator ignores it
Take two charts this page verifies against. Someone born on 15 April 1994 at 00:00 in Los Angeles has a night chart, and a Part of Fortune at Scorpio 7°12′ in the 10th house. Apply the day formula by mistake and you get Aquarius 10°02′ in the 2nd — 92.8° away, a different sign, a different house, a different reading. On a second chart, born 1 April 2000 at 16:00, the error runs to 291.7°. Neither result is subtly off. They are unrelated.
How to Calculate Your Part of Fortune in 3 Steps
Step 1 — Gather the birth data
You need the date, the exact time and the place. The place fixes the horizon; the time fixes the Ascendant, which moves roughly one degree every four minutes. This is the one input you cannot approximate, which is why this page treats a missing birth time differently from most.
Step 2 — Decide day or night
Work out whether the Sun was above or below the horizon at that exact moment. This calculator does it from the Sun’s semi-diurnal arc rather than from the hour on the clock, so it stays correct near sunrise and sunset — and above the Arctic Circle, where the Sun may not rise or set at all on your birth date.
Step 3 — Apply the formula and wrap
Add and subtract the three longitudes according to the sect, then wrap the result into 0–360°: subtract 360 if it overshoots, add 360 if it goes negative. What remains is your Part of Fortune, which then falls into a sign by degree and into a house by your chart’s cusps.
Born Near Sunrise or Sunset? Read This First
One minute, a different chart
Because the two formulas mirror each other, the horizon crossing is a cliff edge rather than a slope. Scanning 1 April 2000 in Los Angeles minute by minute, a birth at 05:43 is still a night chart and gives Taurus 21°05′. A birth at 05:44 is a day chart and gives Pisces 3°02′. Sixty seconds, 48 degrees, a different sign and a different house.
If your birth time was rounded
Recorded birth times are often rounded to five or ten minutes, and hospital clocks are not atomic. If your result card shows the near-crossing warning, treat both candidates as live until you can check the time on your birth certificate. If the certificate itself is vague, the rising sign time scan is the better place to start, because it narrows the Ascendant using events you can actually remember.
Polar births
At high latitudes the Sun may not cross the horizon at all. In Tromsø on 21 December, local noon is still a night chart, because the Sun never rises. On 21 June, local midnight is a day chart. Any tool that decides sect by looking at the clock gets both of these backwards; this one reports the polar case explicitly instead.
The Part of Fortune Through the Signs
How to read your placement
Read the sign as a style of route, not a forecast. The Part of Fortune describes the way of working that costs you least — where effort converts into result without friction. It says nothing about how much arrives, and a placement is not a promise. The most useful question it answers is which of two viable paths will feel less like pushing.
- Aries — the direct route — starting is cheap, deliberating is not
- Taurus — the steady hand — repetition compounds where speed does not
- Gemini — the useful connection — openings arrive through conversation
- Cancer — the safe base — the conditions matter more here than elsewhere
- Leo — the signed work — authored, not anonymous
- Virgo — the fixed problem — improvement that actually ships
- Libra — the good pairing — judgement works best with a counterweight
- Scorpio — the whole truth — depth is cheap, half-commitment expensive
- Sagittarius — the wider frame — scale, not distance, is the mechanism
- Capricorn — the long build — patience is the resource being named
- Aquarius — the odd angle — the sideways route that genuinely works
- Pisces — the permeable route — receptivity as an input, not a plan
Your own placement expands into a three-part reading on the result card above: what tends to come easily, how the placement is commonly misread, and one question you can test against your own history.
The Part of Fortune in the Houses
Why the house needs an exact birth time
The sign tells you the style; the house tells you the arena. Houses are built from the horizon at your birthplace, so they turn on the clock in a way the sign does not — about one degree of Ascendant every four minutes, and a new house every couple of hours. Ten minutes of error is enough to move a Part of Fortune sitting near a cusp into the next house.
The twelve houses, briefly
In the 1st the route runs through your own presence; in the 2nd through what you own and can do; in the 3rd through talking and the immediate neighbourhood; in the 4th through home and roots; in the 5th through what you make and enjoy; in the 6th through daily work and routine.
In the 7th it runs through one-to-one partnership; in the 8th through what is shared and hidden; in the 9th through distance and meaning; in the 10th through public standing; in the 11th through groups and networks; and in the 12th through solitude and work done out of sight.
Enter your details above for the full reading of yours, or see the placement in context in your full birth chart. If the house looks wrong, the usual cause is the birth time rather than the method — the Big Three calculator is a quick way to sanity-check the Ascendant it was built from.
Part of Fortune vs the Other Arabic Parts
The Lot of Spirit is its mirror
The Lot of Fortune has a twin. The Lot of Spirit uses the same three positions with the sect reversed: Ascendant + Sun − Moon by day, Ascendant + Moon − Sun by night. Where Fortune concerns the body, circumstance and what happens to you, Spirit concerns intent and what you choose to do. Traditional practice reads them as a pair.
Which parts are worth your time
Dozens of other lots exist — Eros for desire, Necessity for constraint, and a long tail of highly specific ones. Almost none of them made the journey into modern astrology, partly because their formulas were transmitted inconsistently and partly because Fortune alone carries most of the practical weight. If you are new to lots, learn this one properly before collecting the rest.
Frequently Asked Questions
›Is this Part of Fortune calculator free?
Yes — completely free, with no account, no email and no limit on how many charts you run. Enter a birth date, time and place and your Part of Fortune sign, degree and house appear on this page.
›Do I need my exact birth time?
Yes. The Part of Fortune is measured from the Ascendant, which moves about one degree every four minutes, so a rounded time can move the result into a different house — and near sunrise or sunset it can change the sign as well. Without a time this page shows the whole day rather than a single answer.
›Why do two websites give me a different Part of Fortune?
Almost always because of the day/night formula. A day chart uses Ascendant + Moon − Sun; a night chart uses Ascendant + Sun − Moon. Calculators that apply one formula to everybody are right about half the time and wildly wrong the rest. On a Los Angeles chart from 1 April 2000, a birth at 05:43 gives Taurus 21°05′ and a birth at 05:44 gives Pisces 3°02′.
›What does "day chart" actually mean?
It means the Sun stood above the horizon at the moment of birth — not that it was daytime by the clock. This page works it out from the Sun's position relative to your birthplace horizon, so births just before sunrise are correctly treated as night charts, and polar births are handled properly too.
›How accurate is this calculator?
The Part of Fortune is arithmetic on the Ascendant, Sun and Moon, so it is exact to the arcminute whenever those are. The only thing that can go wrong is the day/night decision, which we compute from the Sun's semi-diurnal arc — including at high latitudes, where the Sun may not rise or set at all on your birth date.
›Is the Part of Fortune the same as good luck?
No, and it is worth being clear about that. Traditionally the Lot of Fortune concerns the body, livelihood and circumstance. Read practically, it describes the route that costs you least — the way of working that tends to go smoothly for you. It does not predict wealth or promise outcomes.
›What house system do you use?
Placidus, the default across this site. Some traditional astrologers place the Part of Fortune using whole-sign houses instead, which can put it one house earlier or later. The sign and degree are the same either way.
›What should I do after I find my Part of Fortune?
Read the sign as the style of the route and the house as the area of life it runs through, then look at the chart around it — the Part of Fortune makes far more sense beside your Sun, Moon and Ascendant than on its own.
Related Tools
Your full natal chart — every planet, house and aspect, with readings.
The Ascendant this point is measured from — exact degree, plus a time scan.
One of the three inputs here: your Moon sign, house and birth phase.
Another calculated point — Black Moon Lilith to the arcminute.
The axis of direction, read as a pair with the South Node.
Sun, Moon and Rising together — the context this point sits in.
The other calculated point worth knowing — sign, house and return.