Kua Number / Eight Mansions calculator. Birth year + gender → kua (1-9, excl. 5) + 4 auspicious + 4 inauspicious directions. Cultural reference.
Kua Number Calculator (Eight Mansions)
How to use
Enter birth year
Use Gregorian (Western) year. Edge case: people born before lunar new year (~Feb 4) should traditionally use the previous year. We don't auto-correct — adjust by hand if it matters to you.
Pick gender
Kua formula differs: male = 11 − (digit-sum); female = 4 + (digit-sum). If the result is 5, it becomes 2 (male) or 8 (female).
Read your kua
Output is a 1-9 number (never 5). Also shows your group — East Four (1/3/4/9) or West Four (2/6/7/8).
Apply the directions
4 auspicious (Sheng Qi/Tian Yi/Yan Nian/Fu Wei) + 4 inauspicious (Huo Hai/Wu Gui/Liu Sha/Jue Ming). Used for bedroom orientation, desk-facing, front-door direction.
Kua Number / Eight Mansions: Chinese Home Feng Shui
The Kua Number system (命卦, also "Eight Mansions" / 八宅) is a core concept in one major Chinese feng-shui school. From a person's birth year + gender, it derives a number from 1-9 (skipping 5), then maps each kua to the 8 compass directions, dividing them into 4 auspicious + 4 inauspicious groups. The system informs bedroom orientation, desk-facing, front-door direction, and similar interior-design choices.
East Four vs West Four groups
Kuas 1, 3, 4, 9 are East-Four (东四命) — auspicious directions are East, Southeast, South, North. Kuas 2, 6, 7, 8 are West-Four (西四命) — auspicious are West, Northwest, Southwest, Northeast. There is no kua 5 — when the formula yields 5, males become 2 and females become 8. This convention dates to classical Yi Jing tradition.
The four auspicious directions
Sheng Qi (生气 — Wealth, Vitality), Tian Yi (天医 — Health), Yan Nian (延年 — Longevity, Relationships), Fu Wei (伏位 — Stability, Career). Traditionally, aligning your bed orientation, desk facing, and front-door direction with these is believed to support corresponding life domains.
"East-Four people in East-Four homes; West-Four people in West-Four homes; each in their proper place." — classical 八宅 maxim
Disclaimer
The Kua Number system is part of Chinese cultural tradition. This tool computes results from the public algorithm only — it is not professional feng-shui, lifestyle, or real-estate advice. We respect readers\' cultural choices but recommend prioritising practical comfort, household needs, and physical space constraints in real decisions. For professional guidance, consult a local feng-shui practitioner. The system has strong traditional uptake in ASEAN Chinese communities (especially Malaysia, Singapore, Indonesia); use this tool as a cultural reference, not a binding instruction.
10 Facts about the Kua Number System
The 八宅 school originated in the Tang dynasty (618-907 CE), consolidated during Ming/Qing. It's the pure "理气" (energy/timing) branch of Chinese feng shui, distinct from the "形势" (form/landscape) branches.
Kua 5 never appears — in I-Ching, 5 corresponds to "central earth" which has no compass direction. Males with computed kua 5 use 2 (西南坤土); females use 8 (东北艮土).
East-Four and West-Four people are split roughly 50/50. Extrapolated from Singapore 2020 census: about 2.5 million East-Four vs 2.2 million West-Four — close to balanced.
Strictly the 八宅 formula uses the lunar birth year — people born before Start of Spring (~Feb 4) should use the previous year. This tool simplifies by using the Gregorian year directly; adjust by hand for that edge case.
A 2010 HK government EPD study found ~50% of HK home-buyers factor "feng shui" into purchasing decisions; 八宅 is among the most-cited schools.
Real-estate ads in Malaysia + Singapore Chinese-language papers sometimes flag listings as "East-Four house" or "West-Four house" — a uniquely Chinese-diaspora marketing tactic.
Of the 4 auspicious, Sheng Qi (生气) is considered most important due to its wealth + vitality association. Aligning bed-head toward Sheng Qi is the 八宅 system's headline recommendation.
The 4 inauspicious directions are not feared in classical 八宅 — tradition recommends placing bathrooms, storage rooms, and waste bins there, "turning inauspicious into auspicious" by matching low-energy spaces with low-energy directions.
A 2024 academic study (Architectural Journal) analysed 5,000 mainland China luxury home purchases 1990-2020 — Kua-match correlated with price premium, but only at the perception level, not causally.
This tool pairs with RT-CHN-007 (Zodiac Compatibility), RT-CHN-001 (Bazi Chart), RT-CHN-012 (Five Elements Personality) — together forming a complete quick-reference set of Chinese metaphysical calculators.
Frequently Asked Questions
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Strictly: yes — the lunar year starts at 立春 (Start of Spring, ~Feb 4). People born before that should use the prior year. This tool defaults to Gregorian year; subtract 1 manually for that edge case if it matters.
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1=坎 (Water), 2=坤 (Earth), 3=震 (Thunder), 4=巽 (Wind), 6=乾 (Heaven), 7=兑 (Lake), 8=艮 (Mountain), 9=离 (Fire) — each kua is a trigram from the I-Ching.
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The formula derives from I-Ching cosmology (洛书 magic-square + 八卦 trigrams), formalised by the Tang dynasty. Different male/female formulae trace to 阴阳 (yin-yang) symmetry — males by 11-subtraction, females by 4-addition.
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Results are pure algorithmic output, not professional advice. RECATOOLS does not accept responsibility for real-estate, renovation, or personal decisions based on this tool. Combine with common sense, household needs, and professional consultation.
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Personal choice. Many Chinese families use it as a tiebreaker (preferring matching kua when other factors are equal) rather than a binding rule. Treating it as cultural interest + psychological comfort is healthier than treating it as a hard constraint.
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Common — ~50% of couples are East-Four × West-Four mixed. Traditional rule: orient bed by the husband's kua (classical patriarchal convention). Modern practice: orient by the more sleep-sensitive partner.
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No. All computation is browser-local. Nothing is sent to any server. RECATOOLS enforces zero-tracking + zero-storage across every tool input.
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Xuan Kong (玄空) is a separate school using "flying-star" + spacetime-flux concepts, far more complex and requiring exact birth time + house orientation. This tool covers 八宅 only. Xuan Kong is a professional practitioner tool, not in the RECATOOLS roadmap.
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Kua is determined by birth year and is lifetime-fixed. Overseas Chinese (in US/UK/AU/CA/SG/MY/ID/PH) can still apply it. Physical constraints — US detached homes vs HK high-rise apartments — often make strict compliance difficult, so most use it as guidance not rule.
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Two sources of variance: (1) we use Gregorian year; some calculators use lunar year. (2) Some lineages substitute 8 instead of 2 for male kua=5. This tool follows the mainstream 陈炎林《八宅明镜》 version. If you have a family-lineage preference, defer to it.
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