Four Pillars of Destiny calculator Bazi · Tứ Trụ · Bát Tự
Bazi, “eight characters”, describes the moment of your birth as four pairs of Heavenly Stems and Earthly Branches. Enter your date and time of birth to see your pillars, your Day Master and its strength, the balance of the five elements and your ten-year luck cycles.
How the Four Pillars are built
Each pillar has a Heavenly Stem on top and an Earthly Branch below. The year pillar changes at the Start of Spring (Lập Xuân), around 4 February, not on 1 January or at Lunar New Year. The month pillar changes at each of the twelve “jie” solar terms, roughly on the 4th to 8th of every Western month. The day pillar follows an unbroken sixty-day cycle, and the hour pillar follows the twelve two-hour periods. Because of these rules the Bazi year and month can differ from the lunar date printed on a calendar, which is why this calculator works from the solar date and exact time.
The ten stems are Jia, Yi, Bing, Ding, Wu, Ji, Geng, Xin, Ren and Gui (Giáp, Ất, Bính, Đinh, Mậu, Kỷ, Canh, Tân, Nhâm, Quý in Vietnamese): Yang and Yin versions of Wood, Fire, Earth, Metal and Water. The twelve branches are the zodiac animals; in the Vietnamese zodiac the fourth animal is the Cat rather than the Rabbit. Every branch also stores one to three hidden stems, which is why a pillar can contain more elements than it shows on the surface.
The Day Master and its strength
The stem of the day pillar is the Day Master, the element that represents you. Everything else in the chart is read in relation to it. A practitioner first asks whether the Day Master is strong or weak: is it in season in the month of birth, does it have roots of its own element in the branches, and do other stems support it? This tool scores those three factors with a weighted count of stems and hidden stems and reports a strong, weak or balanced Day Master.
From that judgement comes the useful element: a weak Day Master is helped by Resource and Companion elements, while a strong one benefits from elements that channel or control its energy. Favourable elements are often used in everyday ways, such as colours, directions or careers, and they help explain why some luck pillars feel easier than others.
The Ten Gods
The Ten Gods (Thập Thần) name the relationship between your Day Master and every other stem, by element and polarity:
| Ten God | Vietnamese | Relationship | Typical themes |
|---|---|---|---|
| Friend | Tỷ Kiên | Same element, same polarity | Peers, self-reliance, confidence |
| Rob Wealth | Kiếp Tài | Same element, opposite polarity | Competition, boldness, shared resources |
| Eating God | Thực Thần | Element you produce, same polarity | Creativity, enjoyment, easy talent |
| Hurting Officer | Thương Quan | Element you produce, opposite polarity | Brilliance, performance, breaking rules |
| Indirect Wealth | Thiên Tài | Element you control, same polarity | Opportunity, business, windfalls |
| Direct Wealth | Chính Tài | Element you control, opposite polarity | Steady income, diligence, thrift |
| Seven Killings | Thất Sát | Element that controls you, same polarity | Pressure, ambition, courage |
| Direct Officer | Chính Quan | Element that controls you, opposite polarity | Status, discipline, responsibility |
| Indirect Resource | Thiên Ấn | Element that produces you, same polarity | Intuition, unusual knowledge |
| Direct Resource | Chính Ấn | Element that produces you, opposite polarity | Learning, support, protection |
Luck pillars
Luck pillars are ten-year periods that follow the month pillar forward for Yang-year men and Yin-year women, and backward for Yin-year men and Yang-year women. The starting age comes from the distance between your birth and the nearest solar term, counting three days as one year. Each cycle adds a new stem and branch to your chart, which is read against your useful and unfavourable elements.
The Tử Vi chart reads the same birth data in a completely different way, and the feng shui directions tool turns your birth year into lucky directions.
Frequently asked questions
Why is my Bazi year different from my zodiac year?
The zodiac animal you hear about usually follows Lunar New Year, while Bazi changes year at the Start of Spring solar term around 4 February. If you were born between those two dates, the two can differ.
Does the birth time really matter?
Yes. The time sets the hour pillar, and it decides the day and month pillars when you were born near midnight or near a solar term. It also sets when your luck pillars begin. If the time is unknown, read only the year, month and day pillars.
Which time zone should I use?
Enter the local clock time where you were born. The calculator treats it as Vietnam time (UTC+7). That only changes the result if you were born within a few hours of a solar term or of midnight; in that case convert your birth time to UTC+7 and compare.
What does a weak Day Master mean?
Weak does not mean unlucky. It means the self element receives less support than the forces it faces, so supportive elements and environments help most. Many successful people have weak Day Masters.
What is nạp âm?
Nạp âm, the “sound element”, gives each of the sixty stem-branch pairs a poetic element name such as Sea Metal or Great Forest Wood. In Vietnam the nạp âm of the birth year is the popular “mệnh” used for compatibility and colours.
How is this different from the Vietnamese Tứ Trụ page?
The calculation is identical. The Vietnamese page adds symbolic stars, monthly luck and a longer written reading; this English page focuses on the core chart.