Calculate the area of an irregular lot

A lot is almost never a rectangle. Measure each side, then the diagonals drawn from one corner: that is enough to know its exact shape and its area.

No account needed. The calculation is done in your browser: nothing is sent.

How it is calculated

The diagonals cut the lot into triangles. Three sides are enough to fix a triangle: its area is computed without knowing any angle. The area of the lot is the sum of the triangles.

Name the corners A, B, C… going around the lot. The diagonals all start from corner A: A–C, then A–D, then A–E. A four-sided lot needs one, a five-sided lot two, a six-sided lot three.

If the tool reports an impossible triangle, a measurement is wrong: in a triangle, each side is shorter than the sum of the other two. Re-measure the diagonal first: it is the hardest one to measure.

The result is as good as your measurements. It is not a boundary survey: only a land surveyor establishes the limits of a property.

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