Irregular Polygon Area Calculator
Find the area of a polygon from up to five vertex coordinates (shoelace formula).
The shoelace formula finds the area of any simple polygon from its vertex coordinates.
The math behind it
List the vertices in order; cross-multiply consecutive coordinates and sum, then halve the absolute value. Leave the 5th vertex at (0, 0) for a quadrilateral.
Worked example
A 4×3 rectangle's vertices give area 12.
FAQ
Does vertex order matter?
List them in order around the polygon (clockwise or counter-clockwise); the absolute value handles the direction.