Circumference Calculator

Find the circumference/perimeter and area of a circle, rectangle, or square

Circumference
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Area
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About this Calculator

The Circumference Calculator computes the distance around a shape (circumference for circles, perimeter for rectangles and squares) along with its area. Pick a shape, enter the dimensions, and get instant results. It is ideal for students, DIY projects, and quick geometry checks — all computed locally in your browser.

Privacy Note: All calculations are performed locally in your browser. No data is ever sent to a server or third party.

Circumference Calculator FAQ

What is the circumference of a circle?
The distance around a circle. It equals 2 × π × radius, or π × diameter.
Circumference vs perimeter?
Circumference is for circles; perimeter is for polygons such as rectangles and squares. Both measure the distance around a shape.
What is π?
π (pi) is the ratio of a circle's circumference to its diameter, approximately 3.14159. It is the same for every circle.