Lu Ban Ruler & Ba Zhai Compass
PAYTANG Lifestyle In-app purchases Contains ads
Feng shui Lu Ban ruler 52.2, 42.9, 38.8 cm plus a Ba Zhai compass by birth year
- Price
- Free
- In-app purchases
- Updated
- Oct 23
- 2026 · v1.0.0
Screenshots
About Lu Ban Ruler & Ba Zhai Compass
Lu Ban Ruler & Ba Zhai Compass helps you choose auspicious sizes and directions when you build or renovate a home, order furniture, open a shop or set up a family altar. It works offline and needs no account.
📏 THREE LU BAN RULERS IN ONE APP
• 52.2 cm ruler: door and window openings, vents, ceiling height.
• 42.9 cm ruler (Yang, 文公尺): desks, beds, kitchen cabinets, shop signs.
• 38.8 cm ruler (Yin, 丁蘭尺): altars and shrines.
• Slide the tape with your finger or type a size in cm, mm or inch. All three rulers update together.
• Red zones are auspicious, black zones are not. See the zone name, its 4 sub-zones and the meaning.
🔴 FIND SIZES THAT ARE RED ON ALL THREE
Enter the size you have (for example a 120 cm desk) and the app finds the closest sizes that land on a red zone on all three rulers, so you change your design as little as possible.
📚 READY-MADE AUSPICIOUS SIZES
Suggested sizes for doors, windows, desks, beds, wardrobes, altars and shop signs. Tap one to open it on the ruler.
📱 REAL 1:1 ON-SCREEN RULER
Measure small objects with your phone. Calibrate the scale with a bank card.
🧭 BA ZHAI (EIGHT MANSIONS) COMPASS
• Enter your lunar birth year and gender to get your Life Gua and East or West group.
• The live compass uses your phone’s sensor and colours your 4 lucky directions (Sheng Qi, Tian Yi, Yan Nian, Fu Wei) and 4 unlucky ones (Jue Ming, Wu Gui, Liu Sha, Huo Hai).
• Placement tips for the front door, desk, bed head, stove and altar.
• Figure-8 calibration guide.
🚗 CAR PLATES & PHONE NUMBERS
Check a plate or phone number with the traditional 80-number method, with every step of the calculation shown.
💾 SAVE & SHARE
Save sizes by group with notes, and share results as an image with family or your carpenter.
🌏 LANGUAGES
English, Tiếng Việt, 繁體中文, 简体中文.
FREE WITH ADS
The app is free and shows ads. Upgrade to Premium (one-time or yearly) to remove ads and unlock the red-size finder without watching videos.
PLEASE NOTE
Results follow traditional feng shui and are for reference only. The app is not a substitute for advice from an architect, builder or other professional.
📏 THREE LU BAN RULERS IN ONE APP
• 52.2 cm ruler: door and window openings, vents, ceiling height.
• 42.9 cm ruler (Yang, 文公尺): desks, beds, kitchen cabinets, shop signs.
• 38.8 cm ruler (Yin, 丁蘭尺): altars and shrines.
• Slide the tape with your finger or type a size in cm, mm or inch. All three rulers update together.
• Red zones are auspicious, black zones are not. See the zone name, its 4 sub-zones and the meaning.
🔴 FIND SIZES THAT ARE RED ON ALL THREE
Enter the size you have (for example a 120 cm desk) and the app finds the closest sizes that land on a red zone on all three rulers, so you change your design as little as possible.
📚 READY-MADE AUSPICIOUS SIZES
Suggested sizes for doors, windows, desks, beds, wardrobes, altars and shop signs. Tap one to open it on the ruler.
📱 REAL 1:1 ON-SCREEN RULER
Measure small objects with your phone. Calibrate the scale with a bank card.
🧭 BA ZHAI (EIGHT MANSIONS) COMPASS
• Enter your lunar birth year and gender to get your Life Gua and East or West group.
• The live compass uses your phone’s sensor and colours your 4 lucky directions (Sheng Qi, Tian Yi, Yan Nian, Fu Wei) and 4 unlucky ones (Jue Ming, Wu Gui, Liu Sha, Huo Hai).
• Placement tips for the front door, desk, bed head, stove and altar.
• Figure-8 calibration guide.
🚗 CAR PLATES & PHONE NUMBERS
Check a plate or phone number with the traditional 80-number method, with every step of the calculation shown.
💾 SAVE & SHARE
Save sizes by group with notes, and share results as an image with family or your carpenter.
🌏 LANGUAGES
English, Tiếng Việt, 繁體中文, 简体中文.
FREE WITH ADS
The app is free and shows ads. Upgrade to Premium (one-time or yearly) to remove ads and unlock the red-size finder without watching videos.
PLEASE NOTE
Results follow traditional feng shui and are for reference only. The app is not a substitute for advice from an architect, builder or other professional.
What’s new
Version 1.0.0 · Updated October 23, 2026
First release: Lu Ban ruler (52.2 / 42.9 / 38.8) with a draggable tape, triple-lucky size finder, Eight Mansions compass by birth year, and licence plate / phone number check. Vietnamese, Traditional & Simplified Chinese, English. Works offline