What is BaZi?
BaZi (八字) means “eight characters.” Each of the Four Pillars contains a heavenly stem and an earthly branch. Together, the year, month, day, and hour form a traditional Chinese birth chart. The stem of the day pillar is called the Day Master.
This calculator presents the chart in English, alongside the Chinese characters. It includes the visible stems’ relationships to the Day Master, commonly called the Ten Gods. Their names are traditional technical labels; “Wealth,” for example, is not a prediction of income. Read the beginner’s guide for the terms used here.
A worked example
For January 7, 2000 at 12:00 in Asia/Shanghai, using the midnight day boundary, the pillars are:
| Year | Month | Day | Hour |
|---|---|---|---|
| 己卯 · Ji Mao | 丁丑 · Ding Chou | 甲子 · Jia Zi | 庚午 · Geng Wu |
The Day Master is Jia, Yang Wood. The year pillar still belongs to the cycle before the next Start of Spring, even though the Gregorian calendar already says 2000.
How time is handled
The year pillar changes at Li Chun (Start of Spring). Month pillars change at the twelve monthly jie solar terms, not on the first day of a Gregorian or lunar month. We compare your birth instant with those boundaries using the calendar library’s UTC+08:00 solar-term clock. Day and hour pillars use the local clock date and time you enter.
Choose your birthplace’s time zone to account for civil clock changes, including summer time where available. A skipped clock time is rejected. If a clock time happened twice when clocks moved back, you must select its first or second occurrence. Historical results depend on the time-zone data supplied by your browser.
The default day boundary is midnight. You can instead select 23:00. Following the library’s convention, the Zi hour stem is calculated from the next day starting at 23:00 in either mode. The calculator does not correct for longitude or the equation of time, so it is a civil-time chart, not a true-solar-time chart. Other schools and calculators can use different conventions.
When your birth time is unknown
We leave the hour pillar blank. If a solar-term boundary makes the year or month uncertain on that date, that pillar is also left blank. Choosing the 23:00 day boundary can make the day pillar and Day Master uncertain too. Element totals cover only the pillars actually shown.
What the element bars count
Each known stem contributes one count to its element; each known branch contributes one to its principal element. Hidden stems, seasonal strength, combinations, and weighting are excluded. This is a transparent count of visible symbols, not an assessment of strength, useful elements, or what you should “add” to your life.
Why does this differ from my animal-year result?
The Chinese zodiac lookup follows Chinese New Year. BaZi year pillars follow Li Chun. A date between those boundaries can correctly produce different year labels under the two methods.
Does the chart include luck cycles or a personalized reading?
This version calculates the Four Pillars, Day Master, visible-stem relationships, and simple element counts. It does not calculate luck cycles, choose useful elements, or generate an AI interpretation.
Calendar engine: lunar-javascript 1.7.7, MIT. See its time-handling notes and our English guide. Method reviewed September 21, 2026. Report a correction.