Triangle Calculator

Calculate triangle area with Heron’s formula and report its perimeter.

How this calculator works

Enter the values for side a, side b, side c. The result applies the displayed method and rounds only for presentation.

Formula / method

Area = √(s(s−a)(s−b)(s−c)), where s is the semiperimeter.

Worked example

Worked example: Side A = 3; Side B = 4; Side C = 5.

Assumptions and limitations

The inputs use the units shown and the displayed triangle calculator method applies to the situation being estimated.

This triangle calculator uses the stated formula and supplied units; unusual inputs, local rules or professional context can change the interpretation.