Free online tool
Free Zi Wei Dou Shu Calculator
Purple Star Astrology (紫微斗數) computed by the classical rules: twelve palaces, the fourteen major stars with the minor star systems, Xun and Jie voids, decade luck cycles and annual readings.
What you need
A Zi Wei chart rests on four facts. Get one wrong and the chart is no longer yours:
- Date of birth — enter the Gregorian date; the tool converts to the lunar calendar and the sexagenary cycle.
- Hour of birth — the most important one. It fixes the Life Palace and the Body Palace.
- Gender — decides the direction of the decade cycles.
- Solar or lunar input — either works; the conversion, including leap months, is handled for you.
What the chart contains
- Twelve palaces — Life, Siblings, Spouse, Children, Wealth, Health, Travel, Friends, Career, Property, Fortune, Parents.
- Fourteen major stars plus the minor systems, the Chang Sheng, Tai Sui and Lu Cun cycles.
- Xun and Jie voids — the “empty” and “severed” markers that soften or cut a palace.
- Decade luck and annual cycles, with the monthly limit shown alongside.
- Star layers can be switched on and off so a beginner is not buried under two hundred names at once.
The 11 p.m. question
This school follows the convention that the Zi hour rolls the date forward: from 23:00 you are already on the next day, while 00:00–01:00 keeps the current date. Schools differ here, so a chart computed elsewhere may place your Life Palace differently. We state the rule openly rather than hide it.
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Frequently asked questions
What is Zi Wei Dou Shu?
A Chinese system of fate analysis, traditionally attributed to Chen Tuan of the Song dynasty. Stars are placed into twelve palaces according to the lunar birth data, and each palace governs an area of life.
Are the stars real stars?
No, and this is the key difference from Western astrology. Zi Wei stars are “virtual”: they are placed by formula from the birth data, not observed in the sky. If you want a system based on real planetary positions, use Qi Zheng Si Yu.
Do I need my exact birth minute?
No. The system uses twelve two-hour periods, so being off by twenty minutes usually does not change anything — unless your birth falls near the boundary of a period.
What if I do not know my birth hour?
You can still build a chart, but its reliability drops sharply, because the Life and Body palaces depend on the hour. A common approach is to try adjacent hours and check each against events that have already happened in your life.
Do I need an account?
No. Building and viewing a chart is free and anonymous. An account is only needed to save charts, compare them, or use the AI interpretation.