Perimeter Calculator

Kite Perimeter Calculator
Enter the two side lengths of a kite to calculate its perimeter using P = 2(a + b). See the total distance around the shape instantly.
Isosceles Triangle Perimeter Calculator
Calculate the perimeter of an isosceles triangle. Enter the lengths of the two equal sides (a) and the base (b) to get P = 2a + b.
Circle Perimeter Calculator
Enter a circle's radius in cm, m, in, or ft to instantly get its perimeter (circumference) using P = 2πr. Fast, accurate, and classroom-ready.
Rectangle Perimeter Calculator
Enter length and width to instantly calculate a rectangle’s perimeter using P = 2(l + w). See the result and your inputs displayed for quick reference.
Square Perimeter Calculator
Enter the square’s side length to get its perimeter (P = 4 × side) — the total distance around the square — instantly.
Octagon Perimeter Calculator
Enter the side length to get an octagon’s perimeter instantly. We multiply the side by 8 (P = 8 × a) for a quick, accurate total.
Hypotenuse Perimeter Calculator
Calculate hypotenuse perimeter quickly and accurately with this easy-to-use calculator. Input side A and side B to find the length of the hypotenuse and total perimeter of a right triangle.