Bazi (Four Pillars) chart calculator. Birth date + hour → 4 pillars (year/month/day/hour) with stem+branch+element+hidden stems+ten gods. Cultural reference.
Bazi Chart Calculator (八字排盘)
How to use
Enter Gregorian birth date
Pick a Gregorian birth date. The tool converts to lunar internally. Supported range: 1900-2100.
Pick birth hour
Enter as HH:MM. Hour-precision is enough (the classical system uses 2-hour blocks). Don't know your exact time? Choose 12:00 for a close approximation.
Pick gender
Bazi uses gender for 十神 (Ten Gods) labelling and 大运 (Major-Cycle) direction calculation. The chart itself is identical; only the relationship labels differ.
Read the chart
You get 4 pillars (year/month/day/hour), each with stem + branch + element + hidden stems + 纳音 + ten-god label. The bar chart at the bottom shows 五行 distribution — useful for spotting excess/deficiency at a glance.
Bazi (Four Pillars): The Core System of Chinese Metaphysics
Bazi — literally "Eight Characters" — also called the Four Pillars system, is the most important and widely-practised branch of Chinese 命理 (fate-reading) tradition, built up across generations of classical fate-reading literature and still the mainstream framework in Chinese-language practice today. The system converts a person's birth year, month, day, and hour into 4 pairs of Heavenly Stem (天干) + Earthly Branch (地支) — 8 characters total, hence the name. Each stem-branch pair is one pillar, and the 4 pillars together form a complete birth chart (命盘).
What each pillar represents
The year pillar represents ancestors + early life (0-15); the month pillar represents parents + youth (16-30); the day pillar represents the self + spouse (31-45, with the day-stem being the "day master" / personal anchor); the hour pillar represents offspring + later life (46+). This four-stage life division is referenced throughout classical bazi analysis.
Reading the Five Elements
Each of the 8 characters belongs to one of the Five Elements (木 wood, 火 fire, 土 earth, 金 metal, 水 water). Their distribution reveals chart balance: excess of one is "strong"; absence is "weak". Classical theory values balance — well-mixed charts are considered hardest to attain and most propitious. The bar chart below shows distribution at a glance.
What a bazi chart shows is never fate's certainty, only fate's possibility — the chart is fixed, what you do with it is not.
Disclaimer + cultural stance
This tool computes bazi from a public algorithm and does not constitute professional advice. Bazi is part of Chinese cultural heritage; its scientific validity as a predictive tool is not supported by modern statistical research. We provide this tool for cultural-tradition preservation + entertainment reference, NOT for major life decisions (marriage, career, health). Always combine with practical considerations and professional consultation. ASEAN Chinese communities (especially HK, Singapore, Malaysia, Indonesia) retain strong cultural interest in bazi; this tool is a self-service cross-reference, not a substitute for a local 命理师 practitioner.
10 Facts about Bazi (Four Pillars)
The traditional lineage account credits Li Xuzhong with reading fate by year, month, and day, and Xu Ziping with adding the hour pillar to complete the four-pillar system — which is where the alternative name 子平术 (Ziping system) comes from. The story is very widely repeated, though its specifics are hard to verify.
Four pillars × 60 stem-branch combos each = 12,960,000 possible bazi charts. But distribution is uneven — some are shared by thousands of people; others occur only once in 60 years.
Everyone born in the same 2-hour block in the same place shares an identical bazi. HK 2020 stats: ~50-60 births per 2-hour block in HK alone — they all share "the same fate". This is the central critique of bazi as a predictive tool.
The "day master" (day-pillar stem) is bazi's most important character — it represents the person. Every other character is read through its relationship to the day master. This is bazi's biggest contrast with Western astrology (which has no analogous focal point).
Balanced 五行 distributions are rare — statistically about 5% of charts. Most people have excess or deficiency in some element, which is why classical bazi books prescribe extensive "补救" (remedies) — wearing certain colours, stones, name changes, directional arrangements.
Bazi 合婚 (marriage matching) is a millennia-old tradition — comparing two people's day-stem + year-branch for harmony/clash. Our companion tool RT-CHN-002 (Bazi Compatibility) handles this use case dedicated.
The "Ten Gods" (比肩 劫财 食神 伤官 正财 偏财 正官 七杀 正印 偏印) are bazi's core vocabulary — each character's yin-yang + element relationship to the day master determines its 十神 label. The tool auto-tags these.
In HK, Taiwan, Singapore, Malaysia, Indonesia Chinese communities, newborn bazi is still widely recorded (especially in birth-memory books). Mainland China retains it in some rural areas but practice has declined notably since the 1990s.
Bazi 大运 (10-year cycles) and 小运 (annual luck) are advanced reading dimensions — not covered in this basic chart tool. Consult a professional 命理师 or specialised software for those.
2024 Google Trends: Chinese-language searches for "八字排盘" peak in January (pre-Lunar-New-Year) and May (matchmaking season) — confirming continued cultural relevance in the diaspora.
Frequently Asked Questions
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Not scientifically validated. Bazi is a millennia-old cultural system, but the "many people share the same chart" phenomenon makes it fail modern statistical scrutiny. This tool does not endorse predictive accuracy — it's for cultural reflection + personal consideration only.
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Pick 12:00 for an approximation. Year/month/day pillars stay accurate (they only need birth date). Only the hour pillar + its associated 十神 are affected. If hour matters to you, check hospital/parental records — or skip hour analysis.
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Two common reasons: (1) 立春 boundary — this tool switches the year pillar at the Start-of-Spring solar term (~Feb 4), some tools use Gregorian Jan 1. (2) Zi-hour boundary — this tool uses early-zi (新日 starts at 23:00); some use late-zi (starts at 00:00).
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The day-pillar stem character. In a bazi chart, the day master represents the person themselves; every other character is interpreted through its relationship (same/conquers-me/I-conquer/produces-me/I-produce) to derive the Ten God labels. The day master's element gives your "element identity" (I'm metal/wood/water/fire/earth命).
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Each earth-branch contains 1-3 "hidden stems" (concealed heavenly stems) in addition to its main reading. For example 亥 contains 壬+甲; 未 contains 己+丁+乙. Hidden stems matter for fine-grained analysis — the visible 8 characters effectively represent 12-15 working characters.
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Yes — HH:MM precision. Classical bazi uses 2-hour blocks (子 to 亥), so minutes don't change the pillar unless you cross a boundary (e.g. 12:59 vs 13:01 switches from 午 to 未). The tool handles boundaries automatically.
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No. All computation is browser-local; no server calls. Even for sensitive metaphysical inputs, RECATOOLS enforces zero-tracking + zero-storage.
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Not as your only guide. Bazi is a cultural-reflection tool, not a decision tool. Major decisions (marriage, career, health, relocation) should rest on practical analysis, professional advice, and personal values. If bazi brings you cultural connection or psychological comfort, that's its value. If it makes you fearful or passive, ignore it.
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大运 are 10-year fortune cycles. 小运 (also "流年") are annual influences. They interact with the natal chart to produce "this decade's flavour" + "this year's flavour" readings. This tool covers the natal chart only; 大运/小运 requires a professional 命理师 or specialised software.
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The basic chart structure matches — stem/branch/element/Ten-God labels follow classical conventions. But higher-level interpretation (格局 chart patterns, 用神 favoured element, 调候 climate balancing) needs human analysis and isn't covered here. Treat this as an introductory + verification tool.
Method & sources
How it computes
The birth moment is converted from the solar calendar to the lunar calendar, and each of year, month, day and hour is expressed as one 天干 and one 地支 — four pillars, eight characters. Each character carries a 五行 element (木火土金水). The 23:00-00:00 hour is treated as belonging to the current day (早子時); under the other school it belongs to the next, which changes the day pillar.
What this tool implements
- Four pillars derived from the lunar conversion of the birth moment, each as a 天干 + 地支 pair, with the 五行 element of each character shown.
- 早子時 (sect 2) is the default: the 23:00-00:00 hour is assigned to the CURRENT day. Under 晚子時 it belongs to the next day and the day pillar changes. A birth in that hour therefore reads differently between schools, and this tool follows the convention used by the majority of modern calculators so a reader comparing against another site sees the same chart.
- The chart is CAST, not interpreted numerically: no score, no ranking, no compatibility percentage is produced from it.
- The page carries a cultural/entertainment-reference notice. What is verifiable here is that the chart is cast correctly for the stated school; what it means is a tradition, not a finding.
Sources
- lunar-javascript v1.7.7 by 6tail, MIT licence: https://github.com/6tail/lunar-javascript — the solar-to-lunar conversion and the 干支 arithmetic. Vendored locally; nothing is fetched at request time. API reference: https://6tail.cn/calendar/api.html
What can make this go out of date
- lunar-javascript is vendored at v1.7.7 and nothing refetches it. Its calendar tables are the dependency: an upstream correction to a lunar conversion reaches this page only on a manual update.
- The 早子時 default is a school choice, not a data feed. If it is ever changed, every chart cast in the 23:00-00:00 hour changes with it.
Pick up where you left off
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