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Polygon Area Calculator

Calculate the area and perimeter of any polygon from its vertex coordinates using the shoelace formula.

Area
12
Perimeter
14
Diagram

How it works

  1. 1Enter each vertex as an x, y pair on its own line — coordinates may be separated by a comma or whitespace.
  2. 2The shoelace formula sums the signed cross-products of consecutive vertices: Area = ½ |Σ (xᵢ yᵢ₊₁ − xᵢ₊₁ yᵢ)|, wrapping the last vertex back to the first.
  3. 3Perimeter is the sum of the Euclidean distances between adjacent vertices, including the closing edge.

Use cases

  • Surveying and land measurement — compute the area of an irregular plot from corner coordinates.
  • Game and graphics development — find the area or bounds of a polygon collision shape.
  • Architecture and interior design — estimate floor or surface area from measured corners.

Frequently asked questions

Does the order of vertices matter?

Yes. List the vertices in consistent order (clockwise or counter-clockwise) around the polygon. The formula works for either winding because the absolute value is taken at the end.

Does it work for concave polygons?

Yes — the shoelace formula works for any simple (non-self-intersecting) polygon, convex or concave. Self-intersecting outlines give incorrect results.

What units does it use?

Whatever units you supply. Coordinates in metres give an area in square metres and a perimeter in metres; feet give square feet and feet.

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