Your Kua Number: How It Is Calculated and What It Decides
The Kua number (卦), also written Gua and known as the Ming Gua (命卦), the "life trigram", is a single digit from 1 to 9 that classical feng shui derives from a person's year of birth and gender. It is not a score and not a fortune: it is an index. Once you know it, one small table tells you which four compass directions support you and which four work against you, and that is what makes the number worth calculating.
The Kua number belongs to Ba Zhai (八宅), the Eight Mansions system, which is the part of the tradition that reads a space for a person rather than for the building. Everything here concerns the number itself and how to use it. The system around it — the eight energies, the palaces and the way a home's grid is built — is set out in the Ba Zhai guide, and this article assumes you have read it.
1. What a Kua number is
A Kua number is a digit from 1 to 9 with one gap in it: there is no Kua 5. The five values that remain in the East group — 1, 3, 4, 9 — and the four in the West group — 2, 6, 7, 8 — are the eight personal trigrams, and each carries a name from the Later Heaven arrangement: Kua 1 is Kan (坎), Kua 2 is Kun (坤), Kua 3 is Zhen (震), Kua 4 is Xun (巽), Kua 6 is Qian (乾), Kua 7 is Dui (兑), Kua 8 is Gen (艮) and Kua 9 is Li (离). The numbers and their trigrams are listed together in the Lo Shu table.
Three properties of the number matter from the start.
- It belongs to a person, not to a property. Two residents of the same flat usually have different Kua numbers, and the flat itself has none.
- It is fixed for life. The number is read from the year of birth, so it never changes, and nothing that happens later revises it.
- It is only about direction. A Kua number says nothing about the shape of a home, the quality of its light, or the condition of its entrance. Those are read by other means.
Because Kua 5 sits in the centre of the Lo Shu grid, it has no direction of its own and cannot be used as a personal number. The classical rule replaces it: a man whose calculation lands on 5 takes 2 instead, a woman takes 8. Anyone who has been told their number is 5 has simply been given an unfinished calculation.
2. How the Kua number is calculated
The calculation takes four steps. It is the one applied by the Kua number calculator, and the order matters.
- Fix the birth year. If the date of birth falls strictly before Li Chun (立春) in that year — the solar term that falls around 4 February — the year used is the previous one. Births on or after Li Chun use the year as written.
- Reduce the four digits of that year to one digit. Add the digits, and keep adding until one digit remains. For 1985: 1 + 9 + 8 + 5 = 23, then 2 + 3 = 5.
- Apply the gender rule. A man subtracts the digit from 11; a woman adds it to 4. Reduce the result to a single digit again.
- Replace a 5. If the result is 5, a man takes 2 and a woman takes 8.
A man born in 1985. 1 + 9 + 8 + 5 = 23 → 5; 11 − 5 = 6. His Kua number is 6.
A woman born in 1985. 1 + 9 + 8 + 5 = 23 → 5; 4 + 5 = 9. Her Kua number is 9.
The first step is where most published calculations go wrong, so it is worth seeing it do something. A man born on 20 January 1985 falls before Li Chun, so his four digits are 1984, not 1985: 1 + 9 + 8 + 4 = 22 → 4, and 11 − 4 = 7. His Kua number is 7, not 6.
3. The two groups
The eight numbers divide into two groups, and the group is what decides which half of the compass is open to you. There is no better or worse group; the East group and the West group each hold four numbers and each own four directions.
| Group | Kua numbers | The four directions that favour them |
|---|---|---|
| East group | 1, 3, 4, 9 | North, South, East, South-East |
| West group | 2, 6, 7, 8 | West, North-West, South-West, North-East |
A useful consequence follows: the four directions that favour an East-group person are exactly the four that disfavour a West-group person, and the other way round. Opposition is structural, not personal, which is why households with both groups in them always involve a trade-off somewhere.
4. The eight directions
Each Kua number has four favourable directions, ranked in a traditional order, and four unfavourable ones, ranked from the merely unhelpful to the most severe. The two tables below are the verified ones used across the whole knowledge base and are reproduced from the reference tables; nothing here is recalculated.
The four favourable directions
| Gua | Palace | Sheng Qi 生气 | Tian Yi 天医 | Yan Nian 延年 | Fu Wei 伏位 |
|---|---|---|---|---|---|
| 1 | Kan | South-East | East | South | North |
| 3 | Zhen | South | North | South-East | East |
| 4 | Xun | North | South | East | South-East |
| 9 | Li | East | South-East | North | South |
| 2 | Kun | North-East | West | North-West | South-West |
| 6 | Qian | West | North-East | South-West | North-West |
| 7 | Dui | North-West | South-West | North-East | West |
| 8 | Gen | South-West | North-West | West | North-East |
The four unfavourable directions
| Gua | Palace | Huo Hai 祸害 | Wu Gui 五鬼 | Liu Sha 六煞 | Jue Ming 绝命 |
|---|---|---|---|---|---|
| 1 | Kan | West | North-East | North-West | South-West |
| 3 | Zhen | South-West | North-West | North-East | West |
| 4 | Xun | North-West | South-West | West | North-East |
| 9 | Li | North-East | West | South-West | North-West |
| 2 | Kun | East | South-East | South | North |
| 6 | Qian | South-East | East | North | South |
| 7 | Dui | North | South | South-East | East |
| 8 | Gen | South | North | East | South-East |
Reading a row is simple once the energies are known. Sheng Qi is the generating energy, the one associated with opportunity and income; Tian Yi is the healing direction; Yan Nian governs relationships and long-term partnership; Fu Wei is stability and quiet continuity. On the other side sit Huo Hai, the least severe, Wu Gui, Liu Sha, and Jue Ming, the direction classical texts treat with most caution.
5. How to use the directions
The directions are used by facing them or by sleeping with the head toward them, and the classical applications are few and specific.
- The bed. The headboard is the traditional use. Facing the head of the bed toward Tian Yi is the health-oriented reading; Yan Nian is used for couples and for a bedroom that needs to hold a relationship steady.
- The desk. A desk is a place of work, so it is read with the career energies: sit facing the Sheng Qi direction where the layout allows, and avoid sitting with your back to a door.
- The door. The door of the room you use most — a bedroom or a study in a flat — is best placed so that you enter from a favourable direction; where the door is fixed, treat it as a condition to work with rather than a fault.
- The seat at the table. A regular seat is a repetition, and repetition is what personal feng shui acts on. Someone who spends two hours a day at a dining table facing Jue Ming has a different situation from someone who passes through that direction once a day.
What the number is not for is deciding where the walls stand. It gives you a way to place furniture, a head, a chair and a habitual position; it does not give you a renovation plan.
6. How not to use the directions
Three limits keep the system honest, and all three are classical.
The map of the home comes first. The form of the property — its shape, its light, the way Qi arrives and moves through it — and the building's own chart outrank any personal direction. A headboard pushed into an awkward corner to catch a favourable compass bearing is a worse bed than one set sensibly against a solid wall. Work from the Bagua map of the floor plan before you reach for the compass.
The front door belongs to the household. A shared entrance cannot face four different favourable directions for four different people. The classical answer is that the door is read for the building, and personal directions are applied to the things a person actually controls: the bed, the desk, the study seat. Trying to optimise an entrance for one resident misreads who the entrance serves.
Personal directions are secondary to the building's chart. In a home whose natal chart parameters show a star in play in a given sector, or where an annual affliction has landed, the personal layer adjusts the reading rather than overriding it. The usual order of judgement is form first, building chart second, person third.
A useful discipline: if a Kua-based recommendation makes a room worse to live in, it has been applied wrongly. The directions are meant to be used where they fit a space that already works. The Five Elements that give the energies their remedies are set out in the Five Elements section, and the practical placements belong to the room articles, not to this table.
7. Why Kua numbers are so often wrong
Most Kua numbers circulating in books and online calculators are simply off by one year, and the reason is the boundary at the start of the calculation.
The birth year is the solar year, not the calendar year. Classical Chinese reckoning runs the year from Li Chun, which falls around 4 February. Anyone born in January or the first days of February belongs to the previous solar year, and that changes the four digits they reduce. Someone born on 30 January 1985 is not a 1985 birth for this purpose; the calculation starts from 1984.
The lunar New Year is not the same date. A common error is to use the Chinese New Year — the spring festival, which moves through late January and February — as the cut-off instead of Li Chun. The two can fall weeks apart, and the Chinese calendar is where that distinction is set out. Calculations that use the lunar date produce two different answers in the same year depending on which festival date is picked.
A 5 is often left as a 5. Some tables simply drop the value, or report it as the centre, when the classical rule is to convert it: 2 for a man, 8 for a woman. A number of 5 in a written answer is a sign that the last step was skipped.
The remedy is unglamorous: fix the year at Li Chun first, then do the arithmetic, then convert a 5. The Kua number calculator applies the boundary for you, and the Kua number pages lay out what each result means.
8. Frequently Asked Questions
How do I calculate my Kua number by hand?
Reduce the four digits of your solar birth year to one digit, then apply the gender rule: a man subtracts that digit from 11, a woman adds it to 4, reducing the answer to a single digit. If you were born before Li Chun — around 4 February — use the previous year. The Kua number calculator does all four steps, including the boundary.
My calculation gave 5. What now?
A result of 5 means the calculation is one step short of finished. There is no Kua 5, because 5 occupies the centre of the Lo Shu grid and holds no direction. Men take 2 instead and women take 8, which places the number in the West group in both cases.
Does my Kua number change if I move house?
No. The number is read from your year of birth and gender and stays with you for life. What changes when you move is the space you apply it to: the same desk orientation may be easy to achieve in one flat and impossible in the next, which is a property of the building rather than of your number.
What happens when my direction is good but the room is not?
The room wins. Form and the building's chart are read before the personal layer, so a favourable bearing that sits in a cramped, dark or badly placed corner is not worth forcing. Personal directions guide furniture, headboards and seating; they do not overturn the layout of a home.
Can two people in one home use the same Kua number?
They can, and where the numbers fall in the same group the recommendations will agree. When two people sit in opposite groups the classical approach is to read the shared spaces for the building and reserve personal directions for what each person controls individually — their side of the bed, their desk, their habitual seat. The Ba Zhai guide covers that reconciliation, and the Eight Mansions section shows the two groups side by side.
