Calculate the perimeter of a triangle given side lengths. Supports equilateral, isosceles, and scalene triangles.

Perimeter: 12.00
Semi-perimeter: 6.00
Area: 6.00
Triangle type: Scalene

Formula: P = a + b + c. Triangle inequality: a + b > c, a + c > b, b + c > a.

Triangle Perimeter

The perimeter of a triangle is the sum of its three side lengths: P = a + b + c. The triangle inequality must be satisfied .

How to Use This Calculator

1. Enter side lengths: Lengths of all three sides.
2. Calculate: Click “Calculate” or press Enter.
3. Interpretation: Results show perimeter, semi-perimeter, area, and triangle type.