📐 Equilateral Triangle Calculator

Calculate area, height and perimeter of an equilateral triangle from side length.

Input Method Side Length

What is an Equilateral Triangle?

A triangle where all three sides are equal and all interior angles are 60°. Knowing any one value allows you to calculate all others.

h = (√3 / 2) × a

L = 3a

S = (√3 / 4) × a² = (1/2) × a × h

a = 2h / √3

L = 2√3 × h

S = (1/√3) × h²

h = √(√3 × S)

a = √(4S / √3)

L = 3a

In an equilateral triangle, all four centers (circumcenter, incenter, centroid, orthocenter) coincide. Circumradius R = a/√3, inradius r = a/(2√3).