Four Pillars
View the year, month, day, and hour pillars. If birth time is unknown, the hour pillar and affected results remain unknown or show candidate boundaries.
Free Bazi chart
Free Bazi Chart Calculator
Enter birth details to create a traceable Four Pillars chart. Location is optional; without one, the calculation uses Asia/Shanghai legal time.
CHART OUTPUT
What can you see after calculating a Bazi chart?
The result separates the natal structure from changes over time so every displayed fact has a clear source.
Five Elements and chart relations
Inspect stems, branches, hidden stems, Ten Gods, element sources, and deterministic combinations, clashes, harms, and penalties without invented strength percentages.
Luck, annual, and monthly cycles
Start from one confirmed natal chart, then layer luck pillars, annual cycles, and monthly cycles in sequence.
Traceable calculation standard
The result preserves the calendar, time mode, place, historical time zone, and algorithm versions that formed the chart.
CALCULATION METHOD
Calculation method and time correction
A Bazi calculator does more than convert a date into stems and branches. Time, place, and exact boundaries can change the resulting pillars.
Birth details
Birth date and calculation sex are required. Birth time can be explicitly unknown, while birthplace remains optional.
No birthplace selected
Without a place, the calculator always uses Asia/Shanghai legal time and never guesses from the browser location or current time zone.
Historical time zones and daylight saving
After a standard place is selected, IANA historical rules resolve the UTC offset and daylight-saving status at the birth time.
True solar time correction
True solar time requires valid coordinates and corrects legal time with longitude and the equation of time; it can change the date, hour branch, or pillars.
Solar-term boundaries
Year and month pillars use the exact solar-term transition instant rather than the first day of a Gregorian or lunar month.
23:00 day boundary
The day pillar changes at 23:00 at the start of the Zi hour. True-solar-time mode applies this rule to the corrected effective time.
Unknown birth time
An unknown time never defaults to 12:00 or an invented hour. The hour pillar and dependent results remain unknown or display candidate states.
DETERMINISTIC & PRIVATE
Deterministic calculation, AI, and privacy boundaries
The deterministic engine calculates pillars, element sources, chart relations, and cycles. AI only interprets a confirmed chart snapshot and never recalculates or rewrites the pillars. Birth details and personal chart results never enter public page content, structured-data Schema, Meta data, the URL, or sharing images. An anonymous temporary chart is restored only through a controlled reference, and the URL contains neither raw birth details nor pillars.
FAQ
Bazi chart questions
Is birthplace required?
No. Without a place, the chart uses Asia/Shanghai legal time. A verified place is required only when true solar time is selected.
How does true solar time work?
Select a standard birthplace result first. The system uses its coordinates and historical time zone before enabling true solar time.
Can I enter a lunar-calendar birth date?
Yes. The lunar picker shows only valid months, leap months, and day counts for that year before converting the date for calculation.
Can I calculate a chart without knowing birth time?
Yes. Mark the time as unknown. The calculator does not insert a default hour, and the hour pillar and dependent results remain unknown or show candidate ranges.
Why does the Bazi day change at 23:00?
This product uses the start of the Zi hour at 23:00 as the day boundary. In true-solar-time mode, the boundary is applied to the corrected effective time.
How are historical time zones and daylight saving handled?
After a place is selected, a locked IANA time-zone version resolves the historical UTC offset and daylight-saving status instead of projecting today's offset backward.
Are birth details or chart results public?
No. Personal birth details and chart results are used only to provide the selected service and never enter public copy, Meta, Schema, or sharing images.