Four Pillars chart
Enter birth time for stems, branches, and elements.
Calculation rules
Four Pillars uses Beginning of Spring for the year and solar terms for months. The selected day boundary applies. Zi Wei uses iztro default stars, lunar New Year, and adjusted leap months: days 1–15 use the current month, later days the next. Schools may differ. Engines: lunar-javascript and iztro.
Privacy and use
No name, account or email required. Birth details remain in page memory and are removed on clear or reload. They are not stored or added to URLs. Only language preference is saved locally. The site is funded by ads: pages load Adsterra ads in an isolated frame, and Adsterra and its partners may receive your IP and browser information and use cookies for ad delivery and measurement (privacy policy: https://adsterra.com/privacy-policy/). The ad frame cannot read this page, and we never provide birth details or charts to advertisers. Visitors in the EEA, UK or Switzerland must agree before ads load. No analytics or external AI requests are enabled. You can refuse ads with your browser's ad or cookie blocking; the tools keep working.
About this tool
BaZi, or the Four Pillars of Destiny, describes a birth moment with one heavenly stem and one earthly branch for each of the year, month, day and hour: eight characters in total. The day stem is the Day Master, the reference point for the Ten Gods.
This tool uses the open-source lunar-javascript library to calculate the pillars, hidden stems, Na Yin, Ten Gods and surface element counts, plus the annual pillar for this year or next. Readings describe the chart's structure as a cultural reference, not a scientific forecast.
FAQ
What do I need to calculate a BaZi chart?
Your Gregorian birth date and birth time in UTC+8 standard time. Without a birth time you still get the year, month and day pillars, plus a table of all twelve possible hour pillars.
When do the BaZi year and month change?
The year changes at Beginning of Spring (Lichun, around February 4) and months change at solar terms, not at Lunar New Year or January 1.
How is a birth between 11 pm and midnight handled?
Schools differ. By default the day changes at midnight; the alternative late-Zi rule starts the next day at 11 pm. You can switch between them in the form.
I was born outside UTC+8. Can I use it?
Yes, but convert your birth time to UTC+8 standard time first. Time zones, historical daylight saving time and true solar time are not handled automatically.
Is my birth data uploaded or stored?
No. Everything is calculated in your browser and kept only in page memory; clearing or reloading removes it.