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Tools
Free online tool

Feng shui ruler — check a measurement online

All four rulers — 52.2 · 48 · 42.9 · 39 cm — with a visual scale showing exactly how far you are from the nearest favourable band.

Feng shui for a home

Pick the right ruler first

This is the step people get wrong, and it matters: the same measurement checked against two different rulers gives two different answers, and both are “correct” for their own ruler.

RulerUse it for
52.2 cmClear opening — the light gap of a door or gate
48 cmSolid bodies and objects
42.9 cmCeiling heights and room dimensions
39 cmGraves, altars, altar tables and cabinets

Measuring a clear opening correctly

Clear opening means the actual gap, excluding the frame. For a door, measure from the inner edge of one jamb to the inner edge of the other, and from the finished floor to the underside of the head.

A great many “it falls in a bad band” results are simply the frame being included. Re-measuring properly often changes the answer by itself.

If it lands badly

The tool draws the ruler visually, so you can see which band you are in and how far the nearest good one is. Usually a few centimetres is all it takes.

For structures that cannot be changed, do not demolish anything over a number: in classical practice a dimension is one factor among many. Function, safety and building codes always come first.

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Frequently asked questions

Why are there several rulers?
Because they were made for different things — openings, solid objects, heights, and funerary or altar work. Each carries its own sequence of favourable and unfavourable bands.
The ruler I bought has two or three rows. Which is which?
Physical rulers often print several scales together without labelling them clearly, which is exactly why it is worth checking here: you choose the ruler explicitly before entering a number, so the rows cannot be confused.
What is the Ya Bai Chi option?
A more advanced reading that considers the facing direction and units taken from the human body. It assumes familiarity with the basic ruler, so start with the main lookup.
Do I have to follow the result?
No. The feng shui ruler is a convention of traditional carpentry and building. It is a cultural reference, and it never outranks safety or the building code.
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