Perimeter Calculator

Calculate perimeter for common shapes quickly.

How to Do It Manually

Perimeter is the total length of all sides of a shape.

Square: 4s | Rectangle: 2(l + w) | Triangle: a + b + c | Circle (circumference): 2πr

Frequently Asked Questions

What is the difference between perimeter and area?

Perimeter is the total boundary length (1D measurement). Area is the space enclosed within (2D measurement).