BaZi Calculator
BaZi, the “eight characters” or Four Pillars of Destiny, covers the year, month, day and hour of birth, each with its own Heavenly Stem and Earthly Branch. The calculator builds a full chart corrected for true solar time and shows everything in it that can be calculated unambiguously.
If the time is unknown, clear the field: the chart will be built without an hour pillar. Longitude and UTC offset are needed only if your city isn't on the list.
What the Chart Shows
- Four Pillars: year, month, day and hour, with the Heavenly Stem and Earthly Branch of each, their element and polarity.
- Ten Gods: how each stem relates to the Day Master, whether it supports, drains or controls it.
- Hidden Stems: one to three inside each branch.
- Na Yin, the “sound element” of each pair, and the Day Master's Life Stages, twelve phases of qi from Birth to Nurture.
- Day Master strength, chart type and useful elements: the main conclusion of the reading, showing what helps the chart, what hinders it, and how this plays out in each decade and year.
- Symbolic stars: Nobleman, Academic Star, Prosperity, Yang Blade, Peach Blossom, Travelling Horse, Flowery Canopy, Void, Kui Gang, White Tiger, Red Beauty, and the 12 Spirits by the year branch.
- Interactions between the pillars: stem and branch combinations, clashes, harms, punishments, mutual resentment and the “Ghost Gate.”
- Luck Pillars for ninety years with the starting age, and Annual Pillars for the next ten years.
- Life Palace, Conception Palace and the Kua number.
You can save the chart as a link, print it or add it to your saved charts. The data never goes into the page address and is not sent to the server. If you press “Read my chart,” the calculated chart is sent to the server — without your birth date, time or place; see the privacy policy for details. To compare two charts, use BaZi compatibility.
How the chart is built
Each pillar is calculated by its own rule — and this is exactly where sites most often disagree.
- The year begins by default not on January 1 but at the moment of Lichun, when the Sun passes 315° of the ecliptic: February 3, 4 or 5. In the lunar variant, it begins at Chinese New Year.
- The month changes by default at the moments of the twelve jie solar terms: Start of Spring, Awakening of Insects, Clear and Bright and so on. These aren't calendar months: the Tiger month runs roughly from February 4 to March 5. In the lunar variant, a month runs from new moon to new moon.
- The day follows a continuous 60-day cycle that hasn't been broken for millennia.
- The hour is one of twelve double hours; its stem depends on the day stem.
The solar term times come from astronomical tables: the Sun's position is calculated with the VSOP87 theory for 1900–2100, and the difference from published data is less than a minute. Time zones and daylight saving changes come from the IANA database built into your browser, so historical offsets — Moscow's UTC+4 in 2011–2014, for example — are accounted for automatically.
True Solar Time
BaZi counts the hour by the Sun, not by the clock. In Moscow, solar noon comes at around 12:30 by the clock, because the city lies west of the middle of its time zone. The calculator makes two corrections: for the longitude of the place (4 minutes per degree) and for the equation of time, a seasonal difference of up to 16 minutes caused by the tilt of Earth's axis and the elongation of its orbit.
If you were born close to an hour boundary, the correction changes the hour pillar, which is why the result shows it on a separate line. Schools argue about whether it's needed at all; you can turn it off.
A separate debate concerns the Rat hour, from 23:00 to 01:00. Some hold that the new day begins at 23:00, others at midnight, assigning the hour from 23:00 to 24:00 to the “late Rat hour” of the old day. The first option is the default; you can choose the second in the form.
Solar or Lunar Calendar
BaZi charts are built with two calendars. In the solar one, the year begins at Lichun and the month follows the jie solar terms. In the lunar one, the year begins at Chinese New Year, and the month is the lunar month from new moon to new moon, the same one that sets the dates of Chinese festivals; in Zi Wei Dou Shu it is the only calendar there is.
The classical texts don't say directly which month to use: they only say that the starting age of the Luck Pillars is counted by the jie solar terms. So the choice is left to the practitioner, and both variants are found in serious schools. By default, the calculator builds the chart on the solar calendar, as is more common, and the “Calendar” setting in the form builds it on the lunar one.
- What changes. The year and month pillars, and with them the Luck Pillars, since they are counted from the month pillar and their direction depends on the year stem. The day and hour pillars are the same in both versions.
- How much changes. If the new lunar month and the jie solar term fall on different days and you were born between them, the month pillar changes and all the Luck Pillars shift by a decade. For people born between Lichun and Chinese New Year, the year changes too, and with it, always, the direction of the Luck Pillars: adjacent years have opposite polarity, while the person's sex stays the same.
- What stays the same. In both versions, the starting age of the Luck Pillars is calculated from the jie solar terms: three days from birth to the nearest jie count as one year. An intercalary (leap) lunar month is treated as the same month as the regular month with the same number.
If the two calendars give different year or month pillars, the calculator shows both versions in the result.
Worked Example
October 1, 1949, 15:00 Beijing time: the moment the People's Republic of China was proclaimed. This chart is often analyzed in textbooks.
- Year. Lichun in 1949 fell on February 4, so this is the Year of the Earth Ox: 己丑.
- Month. The last jie term before the date is White Dew, on September 8, so this is the Rooster month. With the year stem 己, the month stem is 癸, making the pillar 癸酉.
- Day. In the 60-day cycle it is 甲子, the first day of the cycle.
- Hour. 15:00 by the clock is the start of the Monkey hour; for a 甲 day, that's 壬申.
In total: 己丑 · 癸酉 · 甲子 · 壬申, with yang wood 甲 as the Day Master. But with the solar time correction for Beijing (116.4° E), 15:00 becomes 14:55, which is still the Goat hour, and the hour pillar becomes 辛未. That's why different sources give different charts for this date: a single setting decides it.
How the calculator assesses strength and the useful element
Day Master strength and the “useful element” (the element you are advised to strengthen through your profession, colors or directions) are the main conclusion of a master's reading. The calculator works them out according to the classical Zi Ping school (子平):
- Position weights. The year, month and hour stems get 10 points each; the branches get 10 for the year, 15 for the day, 10 for the hour, and 30 for the month branch: the birth season weighs the most. A branch's points are divided among its hidden stems (60, 30 and 10%).
- Strength. The share of points held by the Day Master's element and the element that feeds it. A chart with a share of about 45% is balanced, noticeably more is strong, less is weak. The three classical signs are shown separately: whether the season, the day branch and most of the stems support the Day Master.
- Useful elements. A strong chart benefits from what restrains it or drains its strength, a weak chart from what supports it; which element exactly depends on what dominates the chart. If the Day Master has almost no support and no root (or, conversely, the support is almost 100%), the chart is considered a “following” chart and is read the other way around.
- Climate. People born in winter need Fire, those born in summer need Water; if the season and the balance disagree, the calculator says so.
- Chart type (格局): determined by the stem of the month branch that appears among the chart's stems, or, if there is none, by the main one. A revealed “own” stem (比肩 or 劫财) does not set the type: the chart counts as 建禄 or 羊刃 only when the month branch itself is the Prosperity (Lu) or the Blade of the Day Master; otherwise the next revealed stem, or the main one, is taken.
Based on the useful elements, each ten-year luck pillar and each year is marked as favorable, mixed or difficult. Schools disagree here, and an experienced master may adjust the conclusion by looking at combinations that transform elements and at the person's life. The calculator shows how it arrived at its result so the conclusion can be checked.
How It Differs from the Year-Based Horoscope
The animal-year horoscope uses one of the chart's eight characters — the year branch. It's roughly like judging a person in Western astrology by their Sun sign alone: not exactly wrong, but very crude.
Chinese practitioners regard the "year horoscope" much as astrologers regard magazine horoscopes — and say so openly.
An Honest Look at the Method
BaZi is a coherent, logical system with centuries of history, and it's interesting to work with. But it has no testable predictive power: there are no controlled studies confirming a link between the chart and a person's fate.
Its practical value lies in a structured conversation about yourself, not in forecasting. Decisions about health, money, or marriage shouldn't be based on the chart.
Frequently asked questions
What if I don't know my birth time?
Clear the time field: the calculator will build three of the four pillars. The Luck Pillars are still calculated, but their starting age will be approximate, calculated for noon.
Why did another site give me a different hour pillar?
Most often because of solar time: some sites convert the birth time into true solar time and others don't. The second reason is the day boundary in the Rat hour. Both settings are in the form, and the correction is shown on a separate line in the result.
Why does another calculator give a different month or year pillar?
Most likely it uses the lunar calendar, counting the year from Chinese New Year and the month by lunar months. Switch the “Calendar” setting in the form to Lunar. If the two versions differ, the calculator itself shows in the result which pillars the other calendar would give.
Why are the Luck Pillar ages whole numbers?
That's how practitioners do it: the starting age is rounded to whole years, and the year given is the one in which that age is reached. The calculator gives the exact start of the first pillar above the table.
Why didn't the month change on the 1st?
A Chinese month begins not on the 1st but at the moment of a jie solar term, or, in the lunar variant, at the new moon. If you were born at the start of a month, check the “Month” line in the result: it shows the exact boundaries.
Where is the useful element?
In the “Useful Elements” section below the element balance. The calculator assesses Day Master strength by position weights (the month branch weighs the most), picks the useful, helpful and unfavorable elements, and takes the birth season into account separately. Schools disagree here, so the calculation is shown step by step.
How do I share a chart?
Use the “Copy link” button below the result: it asks whether to add your birth date, time and place to the link. The data never goes into the page address and is not sent to the server.