Enter the four sides of your plot and this tool works out what shape they make, how far the proportions stretch, whether the plot narrows towards the road and what a cut or extended corner means. It then sets each point against what the classical texts say, which is very little, and against what popular modern Vastu adds, which is a great deal more. The two are shown in separate rows. Nothing is scored and nothing is predicted.
What the tool works out
You give the length of the north, east, south and west sides, in feet or metres. Opposite sides are compared. If both pairs match within three per cent, the plot is a rectangle or a parallelogram; if either pair differs, the plot narrows or widens, and the tool says by how much.
Four sides alone cannot fix a shape. A rectangle can be pushed over into a leaning parallelogram without any side changing length. So the tool also takes one diagonal, if you measured it. With a diagonal, the plot splits into two triangles, and the corner angles follow from the law of cosines and the area from Heron’s formula. The tool then tells you whether the corners are square, within three degrees of a right angle, and names the shape: square, rectangle, parallelogram, trapezium or irregular. If the sides and diagonal cannot fit together, it says so and asks you to re-measure instead of guessing.
The result also gives the proportion of the long side to the short side, using the average of each opposite pair, and, if you say which side faces the road, whether the plot is wider at the back or at the front.
What the classical texts say
Very little, and it is worth being plain about that. The one verse read for this site that speaks of shape is Brihat Samhita 53.115. Iyer’s 1884 translation reads it as a caution against ground of irregular shape and irregular sides. Sastri’s 1946 translation reads it as a caution against a site that is not straight, or that faces no particular direction. Both agree on the core: regular ground is wanted, and both attach alarming results in the language of the sixth century. This site does not repeat those results as predictions. The verse is a statement of preference, and the practical answer, in the texts’ time and now, is to set a regular building on the land.
The grid explains the preference. Varahamihira’s results are framed for a site divided into 81 or 64 squares (53.71), which is easy on a square or a rectangle and awkward on anything else. The guide to the Vastu Purusha Mandala shows the grid.
What is modern
The long-side to short-side ratio, the cow-faced and lion-faced labels, and the grading of cut and extended corners corner by corner all belong to later manuals. No classical figure for a ratio was found. The usual statement is that the long side should not pass twice the short side, and some manuals prefer nearer one and a half. A cow-faced plot is narrower at the road and wider behind and is usually favoured for a home; a lion-faced plot is the reverse and is usually favoured for a shop. Manuals disagree about how much taper counts, so the tool only applies either label when the road side differs from the opposite side by at least five per cent.
For corners, a north-east extension is widely praised and a north-east cut widely disliked, the south-west is graded the other way, and the south-east and north-west are mixed. The tool reports these as what is commonly taught and labels them modern. It also tells you how much of the plot’s area the corner represents, which usually shows that a small notch is a very small share of the land. The page on extended and cut corners sets out why the classical verses give no support to the grades.
Reading the result
The result has five parts. The outline row says whether the corners are square and quotes the classical preference. The proportion row gives the ratio and the modern rule of thumb. The taper row appears only if you named the road. The area row appears only if you gave a diagonal, and it is worked out from your own measurements, so check it against the deed. The corner row appears only if you entered a cut or an extension, and carries the classical, modern and practical points together.
A sketch of the plot, with north at the top, is drawn when you give a diagonal. It assumes your sides run to the main directions. A plot turned close to forty-five degrees is better named by its diagonal facing, and the guide to finding which way your house faces explains how.
What to do with the answer
Most plots are not perfect rectangles, and the answer is almost never to change the land. Have the boundary surveyed, mark the setbacks, and draw the largest regular rectangle that fits inside. Plan the house in it, and give the leftover ground a plain use such as a garden, a path or a parking bay. The pages on square and rectangular plots, irregular plots and triangular plots show how.
Nothing here asks for demolition, a bought strip of land or an object placed to complete a corner. The remedies without demolition page explains the free alternatives. Boundaries, setbacks and title are matters for a licensed surveyor, an architect and a lawyer. This tool is a tradition and a geometry check, and it gives no legal, structural or financial advice.
Frequently asked questions
↳ Is a square or a rectangular plot better in Vastu?
Popular manuals usually rank a square first, but the verses read for this site do not rank them. Both are regular shapes, and the classical grid of 81 or 64 squares can be laid over either.
↳ Why does the tool ask for a diagonal?
Four sides do not fix a shape, since a rectangle can lean over without any side changing. One diagonal does, and it lets the tool work out the corner angles and the area. It is optional.
↳ What is a cow-faced plot?
A plot that is narrower at the road and wider behind. Popular manuals favour it for homes and call the reverse, a lion-faced plot, better for shops. This rule was not found in the classical verses read for this site.
↳ Does a cut corner mean the plot is unlucky?
No text read for this site says so. The grading of cut corners comes from later manuals, and no result is claimed here. The tool shows what share of the area is involved, and the practical answer is a regular house with the odd corner put to simple use.
↳ Is the area it gives accurate enough to use?
It is only as accurate as your tape and your diagonal. Use it as a check on your own measurements, and rely on the survey and the deed for anything legal.