Triangle Perimeter Calculator

Calculate the perimeter of a triangle by entering its three side lengths. Also classifies the triangle type.

Side a

Side b

Side c

Enter three sides.

Triangle Perimeter Formula

Perimeter = a + b + c

Example: Sides: 5, 7, 9
Perimeter = 5 + 7 + 9 = 21

Last updated: 2026-08-08