Perimeter Calculator

Choose a rectangle, square, triangle, circle, or regular polygon and calculate its perimeter instantly.

Shape

First value

Second value

Third side

PerimeterLinear units

How to use this Perimeter Calculator

Calculate perimeter or circumference for common 2D shapes. Enter your values above and the result is calculated directly in your browser. No account is required.

Fast answer, clear inputs

This tool is built around one job: give the answer quickly without forcing a signup or hiding the result. Related tools are linked nearby when the next calculation or conversion is useful.