Zi Wei Dou Shu · Purple Star Astrology · free
Enter your date, time and place of birth to see your Zi Wei Dou Shu chart — the twelve palaces with their stems and branches, the fourteen main stars and fourteen auxiliary stars, the Four Transformations of your birth year and the ten-year periods. Calculated from the Chinese lunar calendar, without an account and without AI.
The calculation starts from the Chinese lunar calendar. AstroSensus works out the lunar date of the birthplace’s calendar date from the Moon’s and the Sun’s astronomical positions, with months beginning at the new Moon in China time, as in the published calendar. The Life palace is counted from the Yin branch forward to the lunar month and back by the hour; the Body palace forward by the hour.
Each palace takes a Heavenly Stem by the “five tigers” rule from the year stem. The stem and branch of the Life palace give the Five Element Bureau, a number from 2 to 6, which with the lunar day places the Purple Star, Zi Wei. The other main stars follow from Zi Wei and Tian Fu at fixed distances; the auxiliary stars from the month, the hour and the year.
AstroSensus follows one named convention, the default of the open-source library iztro, and shows every rule next to the result. More than a hundred minor stars, the yearly flow and the small limit are not calculated: we would rather show less than mix schools without saying so.
The classic square chart: twelve palaces with their stems and branches, the Life palace and the Body palace marked.
Zi Wei, Tian Fu and the other main stars, each with its brightness and the image the tradition gives it.
Which stars your birth year turns into Lu, Quan, Ke and Ji, and in which palaces they stand.
The decade periods palace by palace, with ages and years, in both directions the tradition uses.
Want your Western birth chart too — planets, houses and aspects? Open the free birth chart
The other Chinese tradition of the birth moment: the free BaZi (Four Pillars) calculator
Zi Wei Dou Shu (紫微斗數), “Purple Star Astrology”, is a traditional Chinese way of reading the moment of birth. From the lunar date and the hour of birth it lays out twelve palaces — life, siblings, spouse, wealth, career and others — and places stars in them, named after the Purple Star, Zi Wei. It is a symbolic system and a cultural tradition: it describes how the tradition reads a chart, not proven facts about a person.
Both use the Heavenly Stems and Earthly Branches. BaZi reads eight characters taken from the solar terms; Zi Wei Dou Shu uses the lunar date and the hour to place stars in twelve palaces, each palace standing for one area of life. Many readers in Taiwan, Hong Kong, Singapore and Malaysia look at both.
The Life palace is found from the lunar month and the two-hour period of birth, and every other palace and many stars follow from it. Without the hour there is no Zi Wei chart, so the calculator asks for it. If you know only roughly, the result tells you when the time is close to the change of a two-hour period.
The default convention of iztro, a widely used open-source Zi Wei library: the lunar date of the birthplace’s calendar date, the year from the lunar New Year, days 16 and later of a leap month counted as the next month, and iztro’s table of the Four Transformations. The day changes at 00:00; on the result you can switch to a day that starts at 23:00 or to solar time. Schools differ on these points, and the page always shows which rule was used.
Usually because of one of the points where schools differ: a birth in a leap month, a birth between 23:00 and 00:00, or the transformations of a year with the stem Geng, Wu or Ren. The result names each rule it used, so you can compare.
Not in our database. It stays in your browser session for up to two hours and is deleted when you press “Forget my data”. Only if you create an account does it become the first person in that account.