Kua number calculator

Your Kua number comes from your birth year and sex, with the year counted from the beginning of spring rather than 1 January. It sorts the eight compass directions into four that suit you and four that do not.

Eight Mansions uses two formulas and splits them this way. It has no third case.

All eight directions

DirectionVerdictNameAssociated with

The four names on the good side and four on the bad side are traditional. The order within each side is ours — see method.

Why the year starts in February

Eight Mansions counts a year from the beginning of spring (立春), an astronomical moment that falls on 3, 4 or 5 February depending on the year. Someone born in January belongs to the previous year for this purpose. Many calculators hardcode 4 February; across 1900–2100 that is wrong in 73 of 201 years, so this one uses the real date and asks for your birth time only when you were born on the boundary day itself.

Groups, not just numbers

Kua 1, 3, 4 and 9 form the East group; 2, 6, 7 and 8 form the West group. Everyone in a group shares the same four good directions — North, South, East and Southeast for the East group, and Southwest, West, Northwest and Northeast for the West group. What differs within a group is which of the four is strongest for you.

This is also why the two groups can disagree completely about the same bed. A direction that is best for an East group person is one of the worst for a West group person.