Your Kua number, and why it splits households
Four good directions, four bad ones — and a genuine problem when two people disagree.
3 min read · Published 16 August 2026
The short answer
Your Kua number (卦數) is a figure from 1 to 9, excluding 5, calculated from your birth year and your sex, and used in Eight Mansions feng shui to give you four favourable and four unfavourable compass directions. Numbers 1, 3, 4 and 9 are the East group; 2, 6, 7 and 8 are the West group; and the two groups' favourable directions do not overlap at all. Two things trip people up: the year changes at the lunar new year rather than on 1 January, and 5 is redistributed because it has no palace of its own.
How it is calculated
Reduce the digits of your lunar birth year to a single figure. For men born before 2000, subtract that from 10; for men born from 2000, subtract from 9. For women born before 2000, add 5; from 2000, add 6. Reduce again if needed.
If the result is 5, it is redistributed, because the centre of the Lo Shu square has no compass direction: men take 2, women take 8.
The two groups
| Group | Kua numbers | Favourable directions |
|---|---|---|
| East | 1, 3, 4, 9 | North, East, Southeast, South |
| West | 2, 6, 7, 8 | West, Northwest, Northeast, Southwest |
Look at that table for a second longer than feels necessary. The two sets are complements: there is no direction favourable to both groups. That is not a quirk of presentation, it is how the system is constructed.
Which is why households split
A couple, or a houseshare, containing one East group person and one West group person cannot find a front door that is favourable for everyone. Not 'will struggle to' — cannot, because the sets are disjoint.
Any site that takes several birth dates and returns a single happy verdict about a house is averaging that away, and the average is true of nobody in the household.
The traditional remedy is not to argue about the front door. It is to give the person the facing suits least the bedroom that faces their own best direction, and to place desks and beds accordingly within the home. Directions apply room by room, not only at the threshold.
Our home calculator says outright when two residents' charts disagree about an address, names both scores, and gives that remedy.
What the four directions are supposed to do
| Name | Read for |
|---|---|
| 生氣 Sheng Qi | Vitality and progress — the strongest |
| 天醫 Tian Yi | Health and support |
| 延年 Yan Nian | Relationships and longevity |
| 伏位 Fu Wei | Stability and clarity |
The four unfavourable directions have their own names and readings, running from mild irritation to serious misfortune. None of it has been demonstrated, and it costs nothing to angle a desk.
Common questions
- How do I calculate my Kua number?
- Reduce the digits of your lunar birth year to one figure. Men born before 2000 subtract it from 10; from 2000, from 9. Women born before 2000 add 5; from 2000, add 6. Reduce again if needed. A result of 5 becomes 2 for men and 8 for women.
- Why does my Kua number differ between websites?
- Almost always the lunar year. If you were born in January or early February you belong to the previous lunar year, and a calculator using the calendar year will give you a different number and the wrong four directions.
- Why is there no Kua number 5?
- Five sits at the centre of the Lo Shu square and has no compass direction of its own, so it is redistributed: men take 2 and women take 8.
- Can two people in one house have different favourable directions?
- Yes, and if they are in different groups their favourable directions do not overlap at all — the two sets are complements. The traditional approach is to apply directions room by room rather than arguing about the front door.