Four Pillars Calculator

Your Bazi Chart

Enter your birth details to calculate your Four Pillars using documented Zi Ping conventions. Results are generated entirely in your browser.

Birth Details

Adjusts clock time for your longitude difference from the UTC meridian. Note: equation of time is not applied (known limitation).

Zi Hour (子時) convention used on this site: The Zi hour spans 23:00 to 01:00 across midnight. We use the Early Zi convention: births at 23:00 to 23:59 belong to the current calendar day (the day stem before midnight). Births at 00:00 to 00:59 belong to the new calendar day. If your practitioner uses a different convention, adjust accordingly.

The Four Pillars

Day Master (日主)

Your Day Master is the anchor of the chart - the reference point from which all other stems and branches are interpreted.

Five Elements Balance (五行)

Distribution of Wood, Fire, Earth, Metal, and Water across your four pillars and hidden stems.

Day Master Strength (旺衰) and Favourable Elements

Strength is assessed using a simplified rule-based heuristic: seasonal support (月令), rootedness in branches, and stem support. This is a transparent heuristic, not a master's bespoke analysis.

Ten Gods (十神) Mapping

The relationship between your Day Master and each other stem in the chart reveals the Ten Gods - the archetypes that colour different areas of life.

Patterns to Reflect On

Derived from the Ten Gods and element balance. These are patterns for reflection, not predictions.

Favourable Colours and Directions

Based on the favourable elements for your Day Master strength.

Feng Shui Directions

Your Bazi reveals your favourable elements and colours. The Eight Mansions system maps those to compass directions. Calculate your Kua number to find your personal favourable and unfavourable directions.

Save My Chart

Save your chart to this browser. Your data stays on your device and is used to power future daily readings. Nothing is sent to any server.

About Our Method

  • ◆System: Zi Ping (子平) Four Pillars, the mainstream classical method used by most Bazi practitioners.
  • ◆Year boundary: The astrological year begins at Li Chun (立春, roughly February 4), when the sun enters 315 degrees ecliptic longitude. Not January 1 and not the Lunar New Year.
  • ◆Month boundary: Each of the 12 Chinese solar months begins at a Jie (節) solar term. We use a lookup table of accurate solar term dates for 1920 to 2030 (cross-referenced against USNO/Jean Meeus astronomical data).
  • ◆Day pillar anchor: 1900-01-31 (Gregorian) is Jia Zi (甲子), cycle index 0. All day pillars are counted from this documented anchor.
  • ◆Hour stem rule: Five Rats (五鼠遁) - the hour stem is derived from the day stem and the hour branch.
  • ◆Month stem rule: Five Tigers (五虎遁) - the month stem is derived from the year stem and the solar month number.
  • ◆Zi hour convention: Early Zi - births at 23:00 to 23:59 use the current day's stem; births at 00:00 to 00:59 use the next day's stem.
  • ◆Day Master strength: Assessed by a simplified heuristic considering seasonal support (monthly branch), rootedness in branches, and stem support. Stated as simplified on every reading.
  • ◆What this is not: A master's personalised reading. The interpretations are transparent, rule-based outputs. For deep analysis, consult a qualified Bazi practitioner. For Chinese zodiac, we link to birthchartnumbers.com.
For cultural interest and self-reflection only. Not fate, medical, or financial advice.