Four Pillars Calculator — BaZi Year, Month, Day, Hour
Calculate your four pillars and see what each governs: year, month, day and hour — plus why the boundaries are not the ones you expect.
What are the four pillars in BaZi?
A four-pillar chart is the birth moment written as four stem-and-branch pairs — year, month, day, hour. The year pillar is the environment you were born into, the month the season and career field, the day the person themselves, and the hour what comes after. The day stem, called the day master, is the reference everything else is read against.
What each pillar governs
| Pillar | What it covers |
|---|---|
| Year pillar | Family, background, the environment you were born into — and how the wider world reads you. |
| Month pillar | Career and drive. Traditionally the strongest pillar: it shows what you came to build. |
| Day pillar | You. The day stem is the Day Master; the day branch is your spouse palace and your adult self. |
| Hour pillar | Later life, children, output — what you produce and how you finish. |
Why precision matters
The year pillar flips at Chinese New Year, not 1 January. The month pillar flips at the solar term, not the 1st of the month. The day pillar flips at 23:00, not midnight — which is why the traditional day starts at 11pm. And the hour pillar changes every two hours.
Luck pillars: the ten-year chapters
On top of the four static pillars, BaZi adds a sequence of luck pillars (大运) — one per decade. The sequence starts at an age derived from how far your birth date sits from the nearest seasonal boundary, and runs forward or backward depending on your year stem and gender. Each adds a pair of characters that colour that decade.
Reading a chart means holding both layers at once: the fixed structure of the four pillars, and the moving weather of the current luck pillar.
See your four pillars
The calculator is free and lives on the reports page: enter your birth date, time and time zone and it builds the full chart. The written readings below it are optional — one payment each, yours to keep.
See the reports