Can you calculate BaZi without a birth time?
See which parts of a BaZi chart can be shown without an hour, and where solar terms and midnight create uncertainty.
A partial chart is more honest than a guess
You can begin with the recorded birth date and place. Choose “I don’t know my birth time” and GuanXing omits the hour pillar. The remaining chart is provisional: the calculator uses local noon as a reference and labels the missing information.
Year and month can also be uncertain
On a day containing Li Chun or another Jie solar term, two births on the same local date can fall on different sides of the boundary. A noon reference cannot decide which side you were born on. The unknown-hour warning therefore applies to more than the hour column.
Clock correction can change the date
Approximate solar time can move a civil-time birth across midnight. Different late-Zi rules may also give different day pillars for a birth late at night. If you only know “evening,” explore documented possibilities rather than silently turning it into an exact minute.
Recover information before interpreting more
A birth certificate, hospital record or a family recollection may narrow the time. Keep the uncertainty attached to the record. This MVP does not perform birth-time rectification and does not infer a missing hour from personality answers.
Calculation references
- Hong Kong Observatory: stems and branches ↗
- Hong Kong Observatory: 24 solar terms ↗
- lunar-javascript calendar engine ↗