24 Mountains 二十四山 — degrees table & compass converter
Type a compass bearing — the mountain （山）, its trigram palace, your offset from centre, and the risk that you sit on a boundary line all come out, computed entirely in your browser. The full degree table for all 24 mountains is below. Free, no signup, zero network requests.
二十四山 èrshísì shān · each mountain exactly 15° · boundaries at every odd multiple of 7.5°
Convert a bearing 方位角→坐山
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Phone and handheld compasses read magnetic north — convert to true north first (magnetic declination). Facing = sitting + 180°, shown automatically.
The full 24-mountain degree table
Grade-A collated data, identical to the kernel's table; every boundary value is asserted by property tests in the engine. Dragon class: 天 heaven · 地 earth · 人 human — with the yin/yang that steers star flight in flying star charts.
| # | Mountain | Degrees（度域） | Centre | Trigram palace | Yuan-dragon | Yin / yang |
|---|---|---|---|---|---|---|
| 0 | 子 Zi | 352.5°–7.5° （跨 0°） | 0.0° | 坎 N | 天 heaven | 阴 yin |
| 1 | 癸 Gui | 7.5°–22.5° | 15.0° | 坎 N | 人 human | 阴 yin |
| 2 | 丑 Chou | 22.5°–37.5° | 30.0° | 艮 NE | 地 earth | 阴 yin |
| 3 | 艮 Gen | 37.5°–52.5° | 45.0° | 艮 NE | 天 heaven | 阳 yang |
| 4 | 寅 Yin | 52.5°–67.5° | 60.0° | 艮 NE | 人 human | 阳 yang |
| 5 | 甲 Jia | 67.5°–82.5° | 75.0° | 震 E | 地 earth | 阳 yang |
| 6 | 卯 Mao | 82.5°–97.5° | 90.0° | 震 E | 天 heaven | 阴 yin |
| 7 | 乙 Yi | 97.5°–112.5° | 105.0° | 震 E | 人 human | 阴 yin |
| 8 | 辰 Chen | 112.5°–127.5° | 120.0° | 巽 SE | 地 earth | 阴 yin |
| 9 | 巽 Xun | 127.5°–142.5° | 135.0° | 巽 SE | 天 heaven | 阳 yang |
| 10 | 巳 Si | 142.5°–157.5° | 150.0° | 巽 SE | 人 human | 阳 yang |
| 11 | 丙 Bing | 157.5°–172.5° | 165.0° | 离 S | 地 earth | 阳 yang |
| 12 | 午 Wu | 172.5°–187.5° | 180.0° | 离 S | 天 heaven | 阴 yin |
| 13 | 丁 Ding | 187.5°–202.5° | 195.0° | 离 S | 人 human | 阴 yin |
| 14 | 未 Wei | 202.5°–217.5° | 210.0° | 坤 SW | 地 earth | 阴 yin |
| 15 | 坤 Kun | 217.5°–232.5° | 225.0° | 坤 SW | 天 heaven | 阳 yang |
| 16 | 申 Shen | 232.5°–247.5° | 240.0° | 坤 SW | 人 human | 阳 yang |
| 17 | 庚 Geng | 247.5°–262.5° | 255.0° | 兑 W | 地 earth | 阳 yang |
| 18 | 酉 You | 262.5°–277.5° | 270.0° | 兑 W | 天 heaven | 阴 yin |
| 19 | 辛 Xin | 277.5°–292.5° | 285.0° | 兑 W | 人 human | 阴 yin |
| 20 | 戌 Xu | 292.5°–307.5° | 300.0° | 乾 NW | 地 earth | 阴 yin |
| 21 | 乾 Qian | 307.5°–322.5° | 315.0° | 乾 NW | 天 heaven | 阳 yang |
| 22 | 亥 Hai | 322.5°–337.5° | 330.0° | 乾 NW | 人 human | 阳 yang |
| 23 | 壬 Ren | 337.5°–352.5° | 345.0° | 坎 N | 地 earth | 阳 yang |
How the converter judges
- Mountain and palace are arithmetic — 15° sectors, boundaries at odd multiples of 7.5°, facing always sitting + 180°.
- Boundary risk is probabilistic, not a verdict. You state your measurement precision σ; the kernel models the reading as a distribution and reports the probability of a standard chart （下卦）, substitution chart （替卦）, or crossing a palace line （出卦）. When the risk is material it refuses to decide and says why — a phone magnetometer genuinely cannot support a substitution judgement at typical precision.
- Multiple readings? The kernel also accepts sample sets with circular statistics (mean, concentration, κ) — that mode powers the chart verifier; this page keeps it to a single reading for simplicity.
- Unverified table, labelled as such. The 12×30° rule table circulates in some lineages but failed our source-grading; it is available behind an explicit "unverified" toggle, never mixed into the default.
FAQ
What are the 24 mountains in feng shui?
The 24 mountains （二十四山） are the directional sectors of the Chinese compass: eight heavenly stems, twelve earthly branches and four corner trigrams, each spanning exactly 15°. With 0° at north, the Zi mountain runs 352.5°–7.5°. A sitting or facing is always named by its mountain, never a bare degree.
How do I convert my compass bearing to a mountain?
Take the bearing of the sitting (the back of the building), enter it above with your measurement precision, and the converter names the mountain, its trigram palace, your offset from the mountain centre, and whether you are close enough to a boundary for the sitting to be unreliable. Facing is always sitting + 180°.
Magnetic or true north — which does my compass read?
Phone and handheld compass read magnetic north, which differs from true north by the local magnetic declination — tens of degrees in parts of North America and Europe. Convert your reading to true north before using it here; our magnetic declination entry explains the model we use (WMM2025) and its validity window.
What does it mean if my reading falls on a boundary line?
Readings within the last 3°-wide bands flanking a palace boundary are classically dangerous: cross the line and the chart jumps a whole trigram （出卦）, or lands in the substitution zone （替卦）. The kernel quantifies this with probabilities from your stated precision instead of a bare verdict, and refuses to decide when the risk is material.
Why do all the boundary degrees end in .5?
Because 360° divided into 24 equal sectors puts every boundary at an odd multiple of 7.5°: 7.5, 22.5, 37.5 and so on. Our kernel asserts every boundary value by property test, so a corrupted table cannot pass unnoticed.
What is the yuan-dragon (heaven/earth/human) class in the table?
Within each trigram's 45° palace, the three mountains are classed as heaven-, earth- and human-dragon （天元／地元／人元龍）. Each class carries a fixed yin or yang that decides whether stars fly forwards or backwards in a Xuan Kong chart — it is the hinge of the flying-star calculator.
Why 24 sectors and not 8 or 360?
Eight palaces are too coarse to sit a house precisely; a degree scale is meaningless without a compass you can trust to a degree. 24 sectors of 15° each is the traditional resolution the luopan was built around — fine enough to matter, coarse enough to measure with a needle.
Related tools
Flying star calculator · Kua number calculator · 24 Mountains (glossary) · Luopan · Xia Gua / Ti Gua · Methodology