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Perimeter Calculator

Calculate the perimeter of a rectangle, circle or triangle.

Perimeter formulas

The perimeter is the total distance around a shape. A rectangle is 2 × (width + height), a circle's perimeter (circumference) is 2 × π × radius, and a triangle is the sum of its three sides. Choose a shape and enter the values.

Frequently Asked Questions

What is the Perimeter Calculator?

Calculate the perimeter of a rectangle, circle or triangle. It runs instantly in your browser and is completely free.

Is the Perimeter Calculator free and does it require signup?

Yes. Every calculator on Calculatis is 100% free with no registration, and the values you enter are never stored.

How accurate is the Perimeter Calculator?

It uses standard, widely-accepted formulas. Results are reliable estimates for general use and are not a substitute for professional advice.