Triangle calculator

Triangle area with Heron's formula, plus perimeter and height.

Area (Heron's formula)6
Perimeter12
Height relative to side a4

Calculation formula

Area = √(s(s−a)(s−b)(s−c)), where s is half the perimeter

Frequently asked questions

What is Heron's formula?

The area equals the square root of the product of half the perimeter and its difference with each side.

Why isn't a result shown?

The three entered sides must satisfy the triangle inequality; the sum of two sides must be greater than the third side.

Related tools

Related category

All Maths tools