Kua Number Calculator

What a Kua number is

The Kua number (also written Gua, from 卦, "trigram") is the personal number used in Eight Mansions feng shui, called Ba Zhai (八宅) in Chinese. It runs from 1 to 9, but 5 is never used as a final number, so in practice everyone has one of eight Kua numbers. Each one corresponds to a trigram of the bagua and to a home direction.

The number then sorts the eight compass directions into four favorable and four unfavorable ones. Practitioners use those directions to choose which way to face at a desk, which way the head of the bed should point, and which rooms suit which parts of the house.

How the calculation works

Only your birth year and sex go into it — but it has to be the feng shui year, which starts at Lichun (立春), the start of spring, around 4 February. Someone born on 2 February 1990 counts as born in 1989.

1. Find your solar year: if you were born before that year's start of spring, use the previous year.
2. Add the last two digits of the year together, and keep adding until you have one digit. 1984 → 8 + 4 = 12 → 1 + 2 = 3.
3. Women: add 5 (born 1900–1999) or 6 (born 2000 onwards), and reduce to one digit again. 1984 → 3 + 5 = 8.
4. Men: subtract from 10 (born 1900–1999) or from 9 (born 2000 onwards). 1984 → 10 − 3 = 7. A result of 0 counts as 9.
5. If the result is 5, it becomes 2 for men and 8 for women.

The calculator above does the same thing with one formula that works for any year from 1900 to 2100, so there's no separate rule to remember for the 2000s.

The start of spring is not always 4 February

Lichun is a solar term — the moment the sun reaches 315° of ecliptic longitude — so its date moves. Between 1900 and 2100 it falls on 3, 4 or 5 February. The calculator uses the exact moment for every year, in China Standard Time, which is the convention almost all feng shui references follow. If you were born within a day of it, check the time below and remember that your local time zone may move you to the other side of the line.

East group and West group

Kua numbers 1, 3, 4 and 9 form the East group; their favorable directions are North, South, East and Southeast. Kua numbers 2, 6, 7 and 8 form the West group; theirs are West, Northwest, Southwest and Northeast. Two people in the same group share the same four good directions, just in a different order — which is why couples in different groups often look for a compromise bed direction.

The eight directions

"Facing" means the direction you look towards when seated at the desk. For a bed, the usual rule is that the top of your head points to the good direction. Once you know your directions, the house facing finder tells you which way your front door actually points, and the bed and desk tool lets you try them on your own floor plan. To see how your Kua fits the house itself, use Eight Mansions.

Kua numbers by birth year

For a quick lookup. The year is the solar year: if your birthday falls before the start of spring shown, use the row above.

Questions