Equilateral Triangle Calculator

What this calculator does

An equilateral triangle has three equal sides and three 60° angles, so one side length is enough to solve it.

Equal sidesAll three sides are equal.

AnglesAll angles are 60°.

AreaA = √3/4 × side².

For classroom work, check the required rounding rules and whether angles are in degrees or radians. This page uses degrees.

Use Pythagorean theorem or law of cosines depending on the triangle case.

Solve right-triangle side and angle questions with a formula explanation.

Find missing angles from sides or from two known angles.

Solve a triangle when all three sides are known.

Use two sides and the included angle.

Solve common oblique triangle cases.