A two-way Bazi and Gregorian calendar converter with Late Rat Hour (Zi Shi) rule options, designed for Chinese astrology and calendar calculations.
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When you have a Bazi (Four Pillars of Destiny) chart and want to know its exact Gregorian date, or need to convert a known Gregorian birthday into a standard Bazi chart, traditional manual calculation is time-consuming and prone to errors. This tool provides a precise solution for two-way conversion between Bazi and the Gregorian calendar. Bazi, or the Eight Characters of Birth, consists of four pillars (Year, Month, Day, and Hour) represented by the Heavenly Stems and Earthly Branches. The core principle of this tool relies on accurate calendar algorithms to map and calculate the Year, Month, Day, and Hour pillars against Gregorian dates. It also allows users to select different astrological school rules for handling the "Late Rat Hour" (Wan Zi Shi), ensuring accurate conversion results.
Q: What is the purpose of the "Starting Year" when converting Bazi to a Gregorian date?
A: The starting year is the crucial search baseline for reverse-calculating a Gregorian date from Bazi. Because the same combination of Bazi Stems and Branches repeats cyclically throughout history, the tool needs to search within a specific time frame (e.g., 1900-2100) to find the exact date you are referring to.
Q: Which day does the Late Rat Hour (23:00-24:00) belong to in a Bazi chart?
A: This is a common point of debate in Chinese astrology. Our tool provides two options: The "Ziwei School" considers the Late Rat Hour as part of the current day, keeping the Day Pillar unchanged; the "Ziping School" considers it as part of the next day, shifting the Day Pillar forward by one day. You can choose based on the school you study or consult.
Before using, please ensure that the entered Bazi Stems and Branches are correct; incorrect inputs will result in inaccurate searches or no matches. Gregorian date inputs must follow calendar rules (e.g., February 30th is invalid). The tool's calculations are based on algorithms and the selected school's rules, and are intended for astrological research and reference only. This tool does not store any personal birth data entered by users. Please note that Bazi searches over a large year range may take slightly longer, so please be patient.
For astrological research and calendar comparisons, accurate birth hour information is crucial. If you only know the Lunar birthday without the specific hour, we recommend using a Lunar to Gregorian converter first to determine the Gregorian date. Then, use family memory or a birth certificate to estimate the approximate hour (e.g., Rat Hour, Horse Hour) before using this tool for conversion. A typical example: Entering the Gregorian date "January 1, 1990, 23:30" and selecting the "Ziwei School" will yield a Bazi chart with the Day Pillar of the current day; selecting the "Ziping School" will shift the Day Pillar to the next day. Understanding and standardizing the Rat Hour rule is the foundation for ensuring consistency in Bazi charting.
