Your year, month, day and hour pillars — with the Day Master, the hidden stems inside each branch, and the element count.
Pillar boundaries from the Sun's true ecliptic longitude · historic timezones handled · 34,000 cities offline
Korean Saju (사주, 四柱 — "four pillars") and the English "Four Pillars of Destiny" are the same sixty-year stem-and-branch system as Chinese BaZi. A Korean saju reading and a BaZi reading start from an identical grid: year, month, day and hour, each a heavenly stem over an earthly branch. The naming of the stems differs by language; the arithmetic does not. So this page is also a free saju calculator online — the pillars below are what a saju practitioner would write down.
Below the chart you also get the ten-year luck pillars (大运, Da Yun) and the Ten Gods, if you pick a gender — the direction the pillars run depends on it. That is the timing half of BaZi: the eight characters say what the material is, the luck pillars say when it gets worked.
A note on what you will not find here. There is no PDF to download and no app to install. This runs in the browser, and the four stars of destiny sold as e-books are the four pillars you are about to see computed.
Most free BaZi tools look your date up in a table. This one computes where the Sun actually was. The year pillar turns at Li Chun, the moment the Sun reaches 315° of ecliptic longitude, and each month pillar turns 30° later. Those moments fall at a specific hour, not a specific date, so births near a boundary land on the correct side of it.
The other half is the clock. Time zones have moved: peninsular Malaysia and Singapore both shifted to UTC+8 in 1982, Korea changed twice. This calculator uses the offset that was in force in that city on that date, which is what the hour pillar depends on.
The BaZi year turns at Li Chun, when the Sun reaches 315° of ecliptic longitude — around 4 February. Chinese New Year falls on a lunar date that can be two weeks later. If you were born in January or early February, your BaZi animal belongs to the previous year, and this calculator will say so.
For three of the four pillars, no. The hour pillar is the one that needs it, and it changes every two hours. Tick the box and you still get the year, month and day pillars, which is most of the chart.
Local clock time as it stood on the day you were born. Malaysia and Singapore both moved to UTC+8 in 1982; before that the peninsula ran on UTC+7:30. A birth in 1979 is calculated at +7:30, not +8. Calculators that hard-code today's offset get those charts half an hour wrong.
The luck pillars (大运, Da Yun) are ten-year periods that run alongside the birth chart. They step out of the month pillar through the same sixty-step cycle, and the direction of that step is set by two things: whether your year stem is yin or yang, and whether you are male or female. A yang-year man and a yin-year woman move forward; the other two combinations move backward. That is the classical rule, which is why the field is there. Leave it blank and you still get the full birth chart.
The start age is the distance from your birth to the neighbouring jie — the solar term that opens a month — converted at three days to the year, one day to four months. Because that distance is measured in real time rather than whole days, it lands on a specific age rather than a round number. Forward charts count to the next jie, backward charts to the previous one.
Names for the relationship between each character in the chart and your Day Master. Something that generates your element is a Resource; something you control is Wealth; something that controls you is an Officer or Seven Killings. The split between the direct and indirect version of each is polarity: same yin-yang as the Day Master, or opposite. The table counts the hidden stems inside the branches as well as the visible ones.
The heavenly stem of your day pillar. It is the reference point the rest of the chart is read against — which elements support it, which drain it, which it controls.