Equilateral Triangle Calculator

About this calculator

This calculator finds the area, height and perimeter of an equilateral triangle — a triangle where all three sides and all three angles are equal — from a single side length, using formulas derived from the triangle's symmetry: the height splits it into two identical right triangles, which is what makes area and height computable directly from the side using fixed formulas involving the square root of 3.

This shape appears constantly in geometry coursework as the simplest case for practicing area and height formulas, since its symmetry removes the need for a separately measured base and height. It's also used practically in design, construction and fabrication whenever equilateral triangular panels, trusses, tiles or structural elements are being sized, since knowing just one side length is enough to determine every other measurement needed to cut or place the piece.