UtilibyWritten by the Utiliby editorial team · Last updated October 15, 2026 · Rules and formulas reviewed October 2026
What this free online Arabic lots calculator does
Arabic lots, or Arabic parts, are one of the most distinctive tools of traditional astrology. A lot is not a planet: it is a point on the zodiac found by adding and subtracting positions. The best known is the Part of Fortune, but traditional authors used dozens. This free online Arabic lots calculator does the arithmetic for the most documented ones: the Lots of Fortune and Spirit, the five other Hermetic lots, the Lot of Marriage, the Lots of Children and the Lot of Father.
Enter the Ascendant and the seven classical planets. The tool decides whether the chart is a day or night chart, applies the right formula to each lot and shows its sign, degree, sign ruler and house. A wheel marks each lot against the planets, and you can also build a lot of your own. Nothing is uploaded.
How to use the calculator
- Enter the tropical sign, degree and minute for the Ascendant and the Sun, Moon, Mercury, Venus, Mars, Jupiter and Saturn.
- Leave sect on automatic or set it to day or night yourself.
- Choose the options: marriage for men, women or both, the Dorothean or medieval Lot of Children, and whether Fortune is reversed at night.
- Read the table. Each row shows the formula as applied to your chart, so you can check it against your own book.
- Use Build your own lot for any formula of the form Ascendant plus one point minus another.
- Copy the results, download them as CSV or print only the lot table and wheel.
How lots are calculated
Every lot here follows one pattern: Ascendant + A − B, measured in degrees of the zodiac from 0° Aries. You convert each position to a longitude from 0° to 360°, add and subtract, and bring the result back into the range 0° to 360° by adding or subtracting 360. The distance from A to B is then measured out from the Ascendant. If A is the Moon and B is the Sun, the Moon's distance behind the Sun is laid out ahead of the Ascendant, which is why Fortune stands in the same relation to the Ascendant as the Moon does to the Sun in a day chart.
Sect decides which way round the pair goes. In a day chart the formula is read as written. In a night chart many lots swap A and B. This keeps the logic of the lot intact: Fortune by day measures the Moon from the Sun, and by night measures the Sun from the Moon, so that it always counts from the luminary that matters most in that sect.
The lots in this calculator
| Lot | Day formula | Night formula |
|---|---|---|
| Fortune | Asc + Moon − Sun | Asc + Sun − Moon |
| Spirit | Asc + Sun − Moon | Asc + Moon − Sun |
| Eros | Asc + Venus − Spirit | Asc + Spirit − Venus |
| Necessity | Asc + Fortune − Mercury | Asc + Mercury − Fortune |
| Courage | Asc + Fortune − Mars | Asc + Mars − Fortune |
| Victory | Asc + Jupiter − Spirit | Asc + Spirit − Jupiter |
| Nemesis | Asc + Fortune − Saturn | Asc + Saturn − Fortune |
| Marriage (men) | Asc + Venus − Saturn | same |
| Marriage (women) | Asc + Saturn − Venus | same |
| Children (Dorothean) | Asc + Saturn − Jupiter | same |
| Children (medieval) | Asc + Saturn − Jupiter | Asc + Jupiter − Saturn |
| Sons (Valens) | Asc + Mercury − Jupiter | same |
| Daughters (Valens) | Asc + Venus − Jupiter | same |
| Father | Asc + Saturn − Sun | Asc + Sun − Saturn |
Fortune, Spirit and the Hermetic lots are the best documented. For the marriage, children and father lots, authors give different formulas, so treat these as one common version and compare with your own source. The Lot of Father in particular is given in the form above by some modern sources, with extra rules for when Saturn is close to the Sun.
Fortune, Spirit and the Hermetic lots
The Lot of Fortune is the lot of the body, circumstances and material life. The Lot of Spirit is the lot of mind, action and purpose. The other five Hermetic lots build on these two. Eros is the lot of desire and attraction, built from Venus and Spirit. Necessity, built from Mercury and Fortune, concerns constraint and obligation. Courage, from Mars and Fortune, concerns boldness. Victory, from Jupiter and Spirit, concerns success and honours. Nemesis, from Saturn and Fortune, concerns fate, endings and hidden matters. These meanings are traditional associations, not predictions.
Day or night: how sect is decided here
A day chart is one where the Sun is above the horizon. With automatic sect, the tool counts the Sun as above the horizon when it is in houses 7 to 12 counted from the Ascendant sign (whole-sign houses). If the Sun is within a degree or two of the horizon, or your chart uses quadrant houses, check your own chart and set the sect manually. A wrong sect reverses day and night lots and moves them to a completely different place.
Worked example
Take a day chart with the Ascendant at 12°15′ Cancer, the Moon at 3° Gemini and the Sun at 20°10′ Aries. In longitudes these are 102.25°, 63° and 20.17°. Fortune is 102.25 + 63 − 20.17 = 145.08°, which is 25°05′ Leo. The Spirit lot is 102.25 + 20.17 − 63 = 59.42°, 29°25′ Taurus. Counting whole-sign houses from Cancer, Fortune falls in the 2nd house and Spirit in the 11th, ruled by the Sun and Venus respectively.
Common mistakes
- Using the wrong sect. This is the most common reason a lot does not match another program.
- Using sidereal positions. The formulas are traditionally applied to the tropical zodiac.
- Ignoring the source. Many lots have several versions. Compare the formula shown with your book.
- Treating a lot as a planet. A lot is a point of meaning. Its sign ruler, house and the planets aspecting it are what an astrologer reads.
Privacy, limits and responsible use
The calculator runs in your browser. The positions you type are saved in local storage on your device and are never sent to a server. It does not compute planetary positions, hyleg, alcocoden or anareta, and it makes no prediction about health, relationships, money or lifespan. It is meant for study and entertainment. Astrology is an interpretive tradition, not a validated predictive science, and nothing here replaces advice from a doctor, lawyer, financial adviser or mental-health professional.
Frequently asked questions
What is an Arabic part or lot in astrology?
A lot, also called an Arabic part, is a sensitive point found by simple arithmetic on the positions of the Ascendant and two other points. The idea comes from Hellenistic astrology and was widely used by medieval Arabic and Latin authors, which is why they are called Arabic parts.
How do I use this free online Arabic lots calculator?
Enter the sign, degree and minute of the Ascendant, Sun, Moon and the five planets. The table shows each lot, the formula used, the sign and degree, its sign ruler and the whole-sign house it falls in. Everything updates as you type.
How do I calculate the Part of Fortune for a daytime birth?
For a day chart, the Lot of Fortune is the Ascendant plus the Moon minus the Sun. For a night chart the Sun and Moon swap places, giving the Ascendant plus the Sun minus the Moon. A birth is a day birth when the Sun is above the horizon.
How is the Lot of Spirit calculated?
It is the mirror of Fortune: Ascendant plus the Sun minus the Moon by day, and Ascendant plus the Moon minus the Sun by night.
What are the Hermetic lots?
Seven lots transmitted in the Hellenistic tradition: Fortune, Spirit, Eros, Necessity, Courage, Victory and Nemesis. Fortune and Spirit are built from the Sun and Moon, and the other five are built from Fortune or Spirit and a planet.
How do I calculate the Lot of Eros?
By day it is the Ascendant plus Venus minus the Lot of Spirit. By night the pair is swapped: Ascendant plus Spirit minus Venus.
How do I calculate the Lot of Necessity?
By day it is the Ascendant plus the Lot of Fortune minus Mercury. By night it is the Ascendant plus Mercury minus Fortune.
How do I calculate the Lot of Courage?
By day it is the Ascendant plus Fortune minus Mars. By night it is the Ascendant plus Mars minus Fortune.
How do I calculate the Lot of Victory?
By day it is the Ascendant plus Jupiter minus the Lot of Spirit. By night it is the Ascendant plus Spirit minus Jupiter.
How do I calculate the Lot of Nemesis?
By day it is the Ascendant plus Fortune minus Saturn. By night it is the Ascendant plus Saturn minus Fortune.
How is the Lot of Marriage calculated?
In the commonly cited Dorothean form it does not change by sect: Ascendant plus Venus minus Saturn for men, and Ascendant plus Saturn minus Venus for women. Some authors use other versions, such as ones based on the seventh house. The tool shows the formula it used.
Why do day and night charts use different formulas?
Traditional astrology treats day and night as different conditions, called sect. Many lots reverse their formula at night so that the lot keeps the same meaning. A few, such as marriage in the form used here, do not reverse.
What does Ptolemaic Fortune mean?
Ptolemy does not reverse the Lot of Fortune at night. Tick the Ptolemaic Fortune box to use the day formula in every chart. The Lot of Spirit follows the same choice.
Can I build a lot that is not in the list?
Yes. Use Build your own lot to pick any two points, such as the Sun and Saturn, and choose whether the formula reverses at night.
Does it calculate hyleg, alcocoden, anareta, sickness or assets?
No. Those depend on more variable rules and on prediction of lifespan, so they are not included. You can build a lot of your own with a formula from a source you trust.
Is my data stored?
Only in your own browser's local storage, so the page reopens where you left off. Nothing is uploaded. Clear your site data to remove it.
Is astrology scientifically proven?
No. Astrology is a cultural and interpretive tradition, not a validated predictive science. This calculator is for study and entertainment.
Sources and further reading
- Paulus Alexandrinus, Introductory Matters (4th century CE), on the Lots of Fortune and Spirit; Olympiodorus, Commentary on Paulus.
- Vettius Valens, Anthology, translated by Mark Riley (2010), on the lots, including Sons and Daughters.
- Dorotheus of Sidon, Carmen Astrologicum, translated by Benjamin Dykes (Cazimi Press, 2017), on marriage and children.
- Chris Brennan, Hellenistic Astrology: The Study of Fate and Fortune (Amor Fati Publications, 2017), chapter on lots.
- Augurine, Arabic Lots and Parts and Lot of Children, Marriage and Father pages (augurine.com), used to cross-check formulas.
- Kerykeion, Part of Marriage and Arabic parts articles (kerykeion.net), used to cross-check formulas.
Sources were consulted in October 2026. Standards and rules can change, so always check the official page for your situation.