Digital feng shui luopan (compass). On mobile, uses device magnetometer for live bearing; on desktop, manual angle input. Shows 24 mountains + 8 trigrams + live sector readout. Cultural reference only.
Feng Shui Luopan Reader (风水罗盘)
Hold the phone flat, top edge pointing at the main door.
Cultural reference only.
How to use
Pick mode
On mobile: pick "📱 phone compass" (needs HTTPS + sensor permission). On desktop: pick "🖥️ Manual input" and drag the slider.
Calibrate the magnetometer
After starting on mobile, rotate the device slowly in a horizontal figure-8 motion 2-3 times to improve accuracy.
Stay away from metal
Phone magnetometers are highly sensitive to iron, electronics, and magnetic items. Best results outdoors or in an open room.
Read the sector
The right panel shows the current bearing + corresponding mountain name (Ren/Zi/Gui…) + trigram direction (Kan/Li/Zhen…).
Feng Shui Luopan — A 1000-Year-Old Bearing Instrument
The luopan (罗盘) is the core tool of Chinese feng shui — 1000+ years of history. From the Northern Song dynasty Dili Dacheng to the Ming-Qing Luojing Toujie, the luopan grew from 9 layers to as many as 36 in the Qing dynasty, encoding every school\'s direction-element-stem-branch-constellation correspondence in concentric rings.
The 24 Mountains layer
This tool displays the 24 Mountains (二十四山) layer — the most basic directional subdivision of the luopan. Each mountain occupies 15°, totaling 24 × 15° = 360°. Each mountain belongs to one of the 8 trigrams (each trigram covers 3 mountains — e.g. Kan covers Ren/Zi/Gui). All schools — 8-Mansion, Xuan Kong, San Yuan San He — use the 24 Mountains as their foundation.
"The luopan represents engineering application of the magnetic compass — Chinese feng shui practitioners used compasses to guide building orientation 200 years before Europe invented the magnetic compass (11th century)."
Digital luopan vs physical luopan
This tool is a simplified digital luopan — suitable for beginners and at-home self-measurement. Professional physical luopans (HK "Lao Keng Hou" brand, Taiwan "Tsai\'s Luojing") reach 36 layers and cost RMB 800-5,000. Serious feng shui practice uses a physical luopan because phone magnetometer accuracy is limited (±5-10° error).
Phone magnetometer accuracy limitations
Phone magnetometers are Hall-effect sensors designed for navigation (±5° is sufficient). Feng shui luopans require ±1° accuracy — otherwise you may misread on the boundary between two 15° mountains. This tool is suitable for preliminary reference only; serious feng shui analysis needs a physical luopan + licensed practitioner.
Luopan culture in SG/MY/HK/TW
In Singapore, Malaysia, Hong Kong, Taiwan home-buying decisions, practitioners often bring a luopan on-site to measure "sit-mountain" (the direction the house\'s back faces) + "facing" (the direction the house\'s front faces). HK luxury home sales material often includes feng shui master\'s luopan photo as proof of "auspicious orientation".
10 Facts about the Feng Shui Luopan
China invented the magnetic compass. The "Si Nan" (司南) of early texts is often described as a lodestone spoon, though its actual form and date remain debated among historians. The firm documentary landmark is Shen Kuo describing the magnetic needle in the Song-era Dream Pool Essays (《梦溪笔谈》); the needle became the core of the feng shui luopan from there.
The Qing dynasty "Luojing Toujie" (Qianlong era) records luopans reaching 36 concentric layers — including 24 mountains, 120 fenjin, 64 hexagrams, 28 constellations, 24 solar terms — every feng shui dimension encoded.
15° per mountain — not arbitrary. 24 × 15° = 360° complete circle. This is a geometric subdivision: each of 8 trigrams = 45° = 3 mountains.
HK "Lao Keng Hou" brass-shell luopans sell for RMB 2,000-8,000 — considered family heirlooms in feng shui practice. Taiwan's Cai's Luojing (蔡氏罗庚, by Master Cai Mingju) commands even higher prices.
Phone magnetometer vs physical luopan: phone accuracy ±5-10°, physical professional luopan ±0.5°. At the boundary between two 15° mountains, 5° error can misclassify — so this tool is for preliminary reference only.
"Sit-Mountain and Facing" (坐山朝向) are two core house dimensions. Sit = the direction the back faces; Facing = direction the front faces. E.g. "sit north, face south" (坐北朝南) — the most ideal house layout in Chinese tradition.
HK Central + Admiralty + Sheung Wan have the world's highest density of feng shui consultancies — 1-2 professional firms every 200 meters, serving multinational banks, law firms, and private equity funds.
Magnetic North vs True North: the compass points to magnetic north, but traditional feng shui uses true north. The difference is magnetic declination. SG current declination ~0° (negligible), HK ~-2° (magnetic north is 2° west of true).
"Si Nan" (magnetized spoon) is the world's earliest direction-finding device — predating Arab use by 1,300 years and European by 1,500 years. But its engineering refinement into the luopan happened in China in the 11th century.
Pairs with RT-CHN-055 (Bagua House Analysis) and RT-CHN-056 (Annual Fortune) — the complete home feng shui baseline toolkit.
Frequently Asked Questions
Common reasons: (1) HTTPS: DeviceOrientation API requires HTTPS (we support this); (2) iOS 13+ requires permission grant — a prompt appears; select "Allow"; (3) Some Android devices have broken/disabled magnetometers — the tool falls back to manual mode automatically; (4) Desktop browsers have no magnetometer; use manual mode.
Phone magnetometers are highly susceptible to metal objects + electronics + magnetic sources. Common interference: refrigerators, computers, speakers, magnetic phone case clasps, inside cars, subways. Best results outdoors or in an open room after the figure-8 calibration.
iOS's webkitCompassHeading auto-corrects to true north (Apple uses GPS + declination internally). Android's alpha is raw device-relative. This tool prefers webkitCompassHeading (iOS); Android may be slightly off but typically < 5°. Feng shui tradition uses true north.
2 layers: outer ring of 8 trigram directions + inner ring of 24 mountains. This is a simplified version (professional physical luopans reach 36 layers) — suitable for beginners and daily self-measurement.
No — this is a pure web tool. All functionality runs in the browser. No download, no signup. Mobile experience = web page + DeviceOrientation API, comparable to a native app.
No. This is baseline reference with limited precision and only 2 layers. Serious feng shui analysis requires: (1) physical luopan (36 layers, ±0.5° accuracy); (2) licensed practitioner on-site; (3) cross-validation across bazi + annual luck + Xuan Kong + San Yuan multiple schools.
No. The DeviceOrientation API only reads device orientation (α/β/γ rotation angles) — not GPS location. We also upload nothing to any server — all computation happens in your browser.
Yes, recommended. After starting, slowly rotate the device in a horizontal figure-8 motion 2-3 times. This lets the magnetometer re-learn the local magnetic field. Recalibrate at any new location (e.g. when traveling).
Each trigram = 3 mountains; center = "true mountain" (Zi/Wu/Mao/You/Gen/Xun/Kun/Qian). Flanking = "side mountains" using the remaining 8 of the 12 Earthly Branches + 8 of the 10 Heavenly Stems (Jia/Yi/Bing/Ding/Geng/Xin/Ren/Gui). This is a Branches + Stems + Trigrams hybrid system — 24 unique names total.
Yes. All RECATOOLS tools are free (ad-supported). No signup, no paywall.
Method & sources
How it computes
The bearing comes from the device — the phone's orientation sensor where one is available, otherwise a manual 0-360° input — and is mapped onto the two rings a luopan uses: the 二十四山, twenty-four sectors of exactly 15° each beginning at 壬 on 345°, and the eight 八卦 bearings of 45° each. Nothing is fetched and nothing is stored; the reading is a lookup from the angle.
What this tool implements
- 二十四山: twenty-four 15° sectors, the ring used in 玄空 and 八宅 practice to subdivide the eight directions, indexed from 壬 at 345°.
- 八卦方位: the eight trigram bearings at 45° each, on the outer ring.
- ⚠️ A PHONE IS NOT A LUOPAN, and the reading is device-dependent. iOS reports a TRUE heading (webkitCompassHeading); Android reports device-relative rotation about the z-axis (alpha). NO magnetic declination correction is applied — and a traditional 地盤正針 is oriented to magnetic north to begin with. The same spot can therefore read differently on two phones, and differently again from a brass compass.
- The page warns to keep away from metal, electronics and magnetic objects, and offers a manual bearing whenever the sensor is unavailable or permission is refused rather than silently reporting nothing.
- The page carries a cultural-reference notice.
Sources
- W3C DeviceOrientation Event Specification: https://www.w3.org/TR/orientation-event/ — the sensor interface this tool reads, including why the value differs between platforms.
What can make this go out of date
- Browser sensor behaviour, which does change: DeviceOrientation requires HTTPS, iOS requires an explicit permission prompt, and platforms have altered what alpha reports between releases.
- Magnetic declination drifts year on year. Because no correction is applied, that drift is carried into the reading rather than compensated for — deliberately, since the traditional instrument is magnetic too, but it is the reason this cannot be treated as a true-north bearing.
Pick up where you left off
Stored only in this browser — never sent to our servers.