Four Pillars (Saju) Calculator: Free Birth Chart Based on Korean Astrology
Four Pillars (사주팔자) Calculator
The Four Pillars of Destiny (四柱八字) — known as Saju in Korean and BaZi in Chinese — is an East Asian astrological system that reads a person’s character and life patterns from the year, month, day, and hour of birth. Each of the four pillars combines one Heavenly Stem (天干) and one Earthly Branch (地支), producing eight characters total: hence “Eight Characters” (八字). The system cycles on a 60-year Sexagenary basis.
This calculator derives your Four Pillars using pure mathematical calculation — no AI involved.
Understanding the Four Pillars
| Pillar | Represents | Domain |
|---|---|---|
| Year Pillar (年柱) | Birth year | Ancestry, family background, social environment |
| Month Pillar (月柱) | Birth month | Parents, upbringing, career luck |
| Day Pillar (日柱) | Birthday | Your core self (Day Master) · Spouse palace |
| Hour Pillar (時柱) | Birth hour | Children, late-life luck, inner desires |
The Day Master is the key. The Heavenly Stem of the Day Pillar represents “you.” All analysis in Four Pillars astrology is anchored to the Day Master.
The 10 Heavenly Stems
| Stem | Element | Yin/Yang | Symbol |
|---|---|---|---|
| 甲 (Gap) | Wood | Yang | Large tree, beginnings, drive |
| 乙 (Eul) | Wood | Yin | Vine, flexibility, adaptability |
| 丙 (Byeong) | Fire | Yang | Sun, passion, sociability |
| 丁 (Jeong) | Fire | Yin | Candle, intuition, sensitivity |
| 戊 (Mu) | Earth | Yang | Mountain, inclusiveness, stability |
| 己 (Gi) | Earth | Yin | Field, diligence, practicality |
| 庚 (Gyeong) | Metal | Yang | Blade, decisiveness, justice |
| 辛 (Sin) | Metal | Yin | Gem, perfectionism, analysis |
| 壬 (Im) | Water | Yang | Ocean, wisdom, freedom |
| 癸 (Gye) | Water | Yin | Spring water, sensitivity, intuition |
The 12 Earthly Branches
| Branch | Animal | Element | Hours |
|---|---|---|---|
| 子 (Ja) | Rat | Water | 23–01 |
| 丑 (Chuk) | Ox | Earth | 01–03 |
| 寅 (In) | Tiger | Wood | 03–05 |
| 卯 (Myo) | Rabbit | Wood | 05–07 |
| 辰 (Jin) | Dragon | Earth | 07–09 |
| 巳 (Sa) | Snake | Fire | 09–11 |
| 午 (O) | Horse | Fire | 11–13 |
| 未 (Mi) | Goat | Earth | 13–15 |
| 申 (Sin) | Monkey | Metal | 15–17 |
| 酉 (Yu) | Rooster | Metal | 17–19 |
| 戌 (Sul) | Dog | Earth | 19–21 |
| 亥 (Hae) | Pig | Water | 21–23 |
Reading the Five Elements Distribution
The Five Elements — Wood (木), Fire (火), Earth (土), Metal (金), Water (水) — each appear across the eight characters. The balance (or imbalance) reveals which energies dominate your chart.
| Element | Strength Keywords | Challenge Keywords | Lucky Colors |
|---|---|---|---|
| Wood (木) | Growth, creativity, humanitarianism | Indecision, idealism | Green, teal |
| Fire (火) | Passion, charisma, leadership | Impulsiveness, volatility | Red, purple |
| Earth (土) | Stability, trust, practicality | Conservative, slow to decide | Yellow, brown |
| Metal (金) | Decisiveness, justice, structure | Rigid, uncompromising | White, gold |
| Water (水) | Wisdom, adaptability, insight | Anxiety, over-thinking | Black, dark blue |
Complementing weak elements: A common practical application is using colors, directions, or foods associated with a deficient element to bring balance. For example, if Water is weak, incorporating black or dark blue into your environment is suggested.
FAQ
Q. What if I don’t know my birth time?
Select “unknown” — the calculator will default to noon (午時). The three remaining pillars still give a solid basic reading.
Q. Can I enter a lunar calendar birthday?
This calculator uses the solar calendar. Convert a lunar date to solar first, then enter.
Q. Is the Four Pillars system scientifically proven?
No. Saju is a traditional philosophical and cultural system from East Asia with no scientific validation. Use it as a tool for self-reflection and cultural exploration.
Q. What is the Sexagenary Cycle?
60 unique combinations from 10 Heavenly Stems × 12 Earthly Branches (LCM = 60) that repeat on a 60-year cycle: 甲子 (Gap-Ja), 乙丑 (Eul-Chuk), … 癸亥 (Gye-Hae).
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