How this calculator works
BaZi runs on the solar calendar. The year begins at Li Chun 立春, the start of spring, which falls around 4 February. Each month begins at one of the twelve Jie 節 solar terms. These are exact moments rather than dates, so a birth a few hours either side of one can belong to a different month or year. The calculator works out the solar terms to the minute and converts your birth time to the same instant before comparing them, so the time zone matters.
Two conventions are worth knowing. A birth from 23:00 onward counts as the next day, because the Rat hour 子 opens the new day. And the hour pillar uses your local clock time; the calculator does not adjust for true solar time, which can shift a birth near the edge of a two-hour block into the neighbouring hour.
Reading your chart
The Day Master 日主 is the Heavenly Stem of your day pillar. Classical BaZi treats it as you, and reads every other character in relation to it.
The Ten Gods 十神 name those relations. A character of the same element is a Friend or Rob Wealth; the element you produce is your output (Eating God, Hurting Officer); the element you control is Wealth; the element that controls you is Officer or Seven Killings; and the element that produces you is Resource.
Hidden stems 藏干 are the Heavenly Stems stored inside each Earthly Branch. A branch can carry up to three, and they often decide whether an element that looks scarce on the surface is in fact present.
Luck pillars 大運 are ten-year periods that follow the month pillar forwards or backwards, depending on your gender and on whether your birth year is yin or yang. The age they start at depends on how far your birth falls from the nearest solar term.
The element counts show how the eight characters divide among Wood, Fire, Earth, Metal and Water. They are a starting point, not a verdict: judging whether a Day Master is strong or weak also weighs the season of birth and the hidden stems.
BaZi and Purple Star Astrology
Purple Star Chart is built around Zi Wei Dou Shu 紫微斗數, a different Chinese system that places over 100 stars in 12 life palaces using the lunar calendar. The two often disagree, for structural reasons that our guide to Purple Star Astrology vs BaZi explains. If you have your birth details to hand, you can calculate your free Purple Star chart as well.
Frequently asked questions
What is BaZi?
BaZi (八字, "eight characters") is a Chinese system that describes a person through the year, month, day and hour of birth. Each of the four pillars is written as a Heavenly Stem above an Earthly Branch, giving eight characters, and the reading looks at how their five elements support or restrain one another.
Are BaZi, the Four Pillars of Destiny and Saju the same thing?
Yes. Four Pillars of Destiny is the English name for BaZi, and Saju (사주, from 四柱, "four pillars") is the Korean name for the same system. Japanese practice calls it Shichū Suimei 四柱推命. The pillars are calculated the same way in each.
Why is my BaZi year different from my Chinese zodiac year?
The popular Chinese zodiac usually changes animal at the lunar new year, which moves between late January and mid February. BaZi changes year at Li Chun 立春, around 4 February. If you were born between those two dates, your BaZi year pillar belongs to the neighbouring year.
What if I do not know my birth time?
Tick "I don't know my birth time" and the calculator shows the year, month and day pillars, which are six of the eight characters. If a solar term falls on your birth date, it warns you that the month pillar depends on the time.
Does the calculator use true solar time?
No. It uses your local clock time and the time zone you choose. True solar time adjusts the clock for your longitude and the time of year, and it only changes the result when a birth is close to the edge of a two-hour block.
Is my birth data stored?
No. The chart is calculated in your browser and your birth details are not sent to our server.
How is BaZi different from Purple Star Astrology?
BaZi reads the balance of five elements across eight characters taken from the solar calendar. Purple Star Astrology (Zi Wei Dou Shu 紫微斗數) places over 100 stars in 12 life palaces using the lunar calendar. They are separate systems and often describe the same person differently.