Feng Shui & Chinese Zodiac Calculator

About & Methodology

This page explains exactly how the four calculators and the optional full report on this site work, where the rules and data come from, and which questions they deliberately leave open. We keep facts, conventions and open questions separate.

Maintainer: easterncalculators

Review status

The rules below are documented exactly as the calculators apply them. They follow widely published conventions, but they have not been reviewed by an independent feng shui or Chinese astrology practitioner. Where traditions disagree and the site has not adopted one convention, it calculates nothing rather than show an invented result.

Kua number (Eight Mansions)

  1. Resolve the traditional year (see year boundary).
  2. Add the last two digits of that year repeatedly until one digit remains: S.
  3. Born 1900–1999: male Kua = 10 − S (10 becomes 1); female Kua = S + 5, reduced to one digit.
  4. Born 2000–2099: male Kua = 9 − S (0 becomes 9); female Kua = S + 6, reduced to one digit.
  5. Kua 5 does not exist (the center of the Lo Shu square has no trigram): male 5 becomes 2, female 5 becomes 8.

Kua 1, 3, 4, 9 are the East group; 2, 6, 7, 8 the West group. Each Kua number maps to a trigram (1 Kan, 2 Kun, 3 Zhen, 4 Xun, 6 Qian, 7 Dui, 8 Gen, 9 Li) and to the standard Eight Mansions table of four favorable directions (Sheng Qi, Tian Yi, Yan Nian, Fu Wei) and four unfavorable directions (Huo Hai, Wu Gui, Liu Sha, Jue Ming). The full table is on the Feng Shui Calculator page.

Compass orientation: every compass and luopan drawing on this site puts North at the top, matching how the calculators read directions (as on a map). Traditional luopan plates are usually drawn with South at the top, so the picture is turned 180° compared with many printed luopans; the directions themselves are the same.

Source note: the formula is commonly attributed to the classical Eight Mansions text Ba Zhai Ming Jing (八宅明镜). We have not verified this attribution against a primary edition.

Annual Flying Stars (full report only)

The free calculators use Eight Mansions only. The optional full report adds one more layer: the annual Flying Star chart, laid over your personal Eight Mansions directions. It is a separate classical method, and the report labels it as such.

The report lists each star with its traditional element and reading. Readings follow the common convention for the current Period 9 (2024–2043); they are traditional associations, not predictions.

Year boundary: Li Chun and Lunar New Year

The traditional year does not start on January 1. Two standards are in common use:

Births before both dates belong to the previous year under either standard. For births between the two dates, or on the Li Chun day itself (where the time of birth matters), the standards disagree.

Default standard by tool. The site keeps both standards and gives each tool a primary one:

Every result names the primary standard it used. When the two standards give different years, the result shows both: the primary result first and the comparison result next to it, with a note explaining why they differ. On the Li Chun day itself the Li Chun year depends on the time of birth, so both possible Li Chun years are shown.

Data: the site includes a table of Li Chun date and time and Lunar New Year date for every year 1920–2030, in China Standard Time (UTC+8). It was generated with the open-source library lunar-javascript 1.6.12 and independently cross-checked: Lunar New Year against lunardate 0.3.0, and Li Chun against an astronomical calculation with PyEphem 4.2.1. All 111 years matched to the day; Li Chun times agreed to within a minute.

Limitation: the calculators compare the calendar date you enter with these China Standard Time dates. Birth time and time zone are not collected, so a birth close to a boundary may need checking by hand.

Chinese zodiac relations

The animal sign and year element come from the sexagenary year: Heavenly Stem = (year − 4) mod 10 (Jia, Yi = Wood; Bing, Ding = Fire; Wu, Ji = Earth; Geng, Xin = Metal; Ren, Gui = Water), and Earthly Branch = (year − 4) mod 12 (Rat … Pig). Both use the boundary-resolved year.

The compatibility calculators check these traditional earthly-branch relations:

Year elements are compared with the Wu Xing generating cycle (Wood → Fire → Earth → Metal → Water → Wood) and controlling cycle (Wood → Earth → Water → Fire → Metal → Wood).

Tier order. To summarize a pair, the calculators use a simplified order of the traditional relations: Liu He (highest), then San He, then same sign or no relation, then punishment, harm and clash (challenging). It is a reading aid, not a classical ranking, and schools weigh these relations differently. Pairs with both a harmony and a conflict-type relation, and pairs whose only relation is Xiang Po, do not fit this order and are labelled "No single tier". By design, the site gives no percentages, star ratings or numeric scores: a match is described by its traditional relations (Liu He, San He, clash, harm, punishment, destruction) and a qualitative tier label. The marriage calculator adds four dimensions (Long-Term Stability, Emotional Bond, Family & Finance, Conflict Resolution), each with a short traditional note for the pair's type of relation, without scoring them.

Your data

All calculations run in your browser. See the privacy policy.

What this site does not do

It does not calculate BaZi (Four Pillars), Na Yin elements or a house's natal Flying Star chart (the annual chart in the full report is described above), and it does not give medical, legal, financial or marriage advice. See the disclaimer.