Free BaZi Calculator (Four Pillars)

BaZi (八字, literally "eight characters"), also known as the Four Pillars of Destiny, reads a person's makeup from the four stem-branch pairs of their birth year, month, day and hour. It took shape in the Tang and Song dynasties and matured through the Ming and Qing, making it the longest-lived and most widely practiced system of Chinese astrology.

Each pillar combines one Heavenly Stem (甲乙丙丁戊己庚辛壬癸) with one Earthly Branch (子丑寅卯辰巳午未申酉戌亥) — four pillars, eight characters. Every stem and branch maps to one of the five elements (wood, fire, earth, metal, water), which generate one another (wood feeds fire, fire creates earth…) and control one another (wood breaks earth, earth dams water…). Your chart is a dynamic system of elemental forces: which elements are strong, which weak, and how they balance forms your chart structure. At the center stands the Day Master — the stem of your day pillar, representing you — and every other character is read by how it supports or drains the Day Master.

Compared with Zi Wei Dou Shu, BaZi is more abstract and inferential: it excels at judging structural strength and identifying your favorable elements. And a reminder that applies to every system: a chart describes innate configuration and tendencies — it is not an unchangeable sentence.

Step 1: enter your birth date in the solar (Gregorian) calendar. The tool converts to the stem-branch calendar automatically. Note that the BaZi year begins at Li Chun (the "Start of Spring" solar term, around February 4) — not at Lunar New Year — and months are bounded by solar terms; the tool handles all of this for you.

Step 2: enter your birth time. The hour pillar follows the traditional two-hour periods (23:00–00:59 is the Zi hour). A birth time that crosses a boundary changes your hour pillar — and births near 23:00 are the trickiest case, since schools differ on how the late-night Zi hour assigns the day pillar. Use the most accurate time you have.

Step 3: enter your birth city and pick a suggestion (the time zone fills automatically), choose your gender (it sets the direction of your luck cycles together with the year stem's polarity), and press the button. Your pillars, Ten Gods table and element distribution render right on the page.

An honest disclosure: this tool casts your pillars from the local clock time you enter — no true solar time correction is applied. True solar time takes the sun's actual crossing of your local meridian as noon; depending on your birthplace's longitude within its time zone and the equation of time, it can differ from clock time by several minutes to over an hour. Some practitioners insist on true solar time for the hour pillar; many others cast by clock time. We choose not to make that call silently for you — the input stays under your control.

To cast with true solar time, correct the time yourself before entering it: (1) find your birthplace's longitude; (2) for each degree it differs from your time zone's central meridian (e.g. 120°E for Taiwan, 75°W for US Eastern), add or subtract 4 minutes — east of the meridian adds, west subtracts; (3) apply the equation of time for your birth date (roughly −14 to +16 minutes, available in astronomical almanacs). Example: born in Taipei (121.5°E), the longitude correction is about +6 minutes.

If you were born during daylight saving time, subtract one hour from the recorded clock time first. Year and month pillars are derived precisely from solar terms (Li Chun boundary, twelve monthly terms) with leap months handled automatically — small clock-time inaccuracies do not affect them.

Year pillar: your ancestry, grandparents and the era you were born into; traditionally governs roughly ages 1–16. Its relationship to the Day Master hints at early environment and elder support.

Month pillar: the "framework" of the chart — parents, siblings, upbringing, and roughly ages 17–32. The month branch (the "month command") is the single most important character for judging the Day Master's strength: whether your day stem is "in season" for your birth month is step one of structural analysis.

Day pillar: the day stem IS the Day Master — you. Its element and polarity give your core imagery: Jia is towering timber, Yi a climbing vine, Bing the blazing sun, Ding candlelight, Wu the mountain, Ji fertile soil, Geng raw steel, Xin refined jewels, Ren the great river, Gui the morning dew. The day branch is the spouse palace, describing marriage and intimacy, and covers roughly ages 33–48.

Hour pillar: children, subordinates and later life (roughly age 49 onward) — your legacy and where things settle. Its relationship with the Day Master is read for the quality of later years and the bond with children.

Once the pillars are cast, locate your Day Master (the tool highlights it), then read every other character through its relationship to the Day Master — which brings you to the Ten Gods.

The Ten Gods (十神) are BaZi's core vocabulary: they translate each stem's elemental relationship to your Day Master — same element, produces me, I produce, controls me, I control — crossed with matching or opposite polarity, into ten archetypal roles: Companion and Rob Wealth (peers), Eating God and Hurting Officer (output and talent), Direct and Indirect Seal (resources and learning), Direct Officer and Seven Killings (discipline and pressure), Direct and Indirect Wealth (income and opportunity).

Each carries its own meaning: Direct Officer stands for discipline, institutions and rank; Seven Killings for boldness, competition and pressure; Direct Seal for learning, protection and security; Indirect Seal for specialized skill and intuition; Direct Wealth for steady income and pragmatism; Indirect Wealth for fluid money and business instinct; Eating God for talent and easy expression; Hurting Officer for brilliance, innovation and irreverence; Companion for selfhood and cooperation; Rob Wealth for drive, rivalry and spending risk.

The table below your chart lists the Ten God of each pillar's stem AND of every hidden stem (the stems concealed inside each earthly branch — e.g. the Yin branch hides Jia, Bing and Wu). Hidden stems are where BaZi gets subtle: forces not visible on the surface live inside the branches. A beginner's exercise: count which category dominates. Officer/Killings-heavy charts prize achievement and rules; Seal-heavy charts prize learning and inner life; Wealth-heavy charts are pragmatic and resource-minded; Output-heavy charts are expressive and averse to constraint; Peer-heavy charts are strong-willed with wide networks.

The distribution chart counts wood, fire, earth, metal and water across your four stems, four branches and all hidden stems, giving an at-a-glance picture of your chart's elemental lean. A caveat: raw counts are only a beginner's approximation — professional analysis weighs the month command most heavily and accounts for position, combinations and clashes. Three fire characters born in midwinter and three born in midsummer are entirely different animals.

"Favorable elements" (喜用神) are where BaZi becomes practical: a Day Master that is too strong favors the elements that drain or control it; one that is too weak favors the elements that feed it. Once identified, favorable elements map onto directions, colors, industries and timing. This judgment takes real skill — treat this tool's output as your raw data, and pair it with a systematic reading. That is exactly what the AskStar AI report does: it cross-references your BaZi, Zi Wei and Western charts into one coherent interpretation.

The stem-branch conversion uses a widely validated calendar engine: year pillar bounded by Li Chun, month pillars by the twelve solar terms, day pillar switching at midnight, hour pillar by the two-hour periods. Anonymous birth data is used only for the immediate calculation and never stored. See /methodology for the full write-up. When results differ from another calculator, the usual causes are hour-boundary rounding, the true-solar-time choice, or the late-Zi-hour school difference.