Circle Calculator: Quickly Calculate Radius, Diameter, Circumference & Area

This easy-to-use tool helps you calculate essential circle properties, such as radius, diameter, circumference, and area, in just a few clicks. Whether you’re solving geometry problems, working on a project, or just curious, our calculator delivers accurate results instantly.

Calculate From Radius (r)

Radius (r): The distance from the center of the circle to any point on its edge.

Calculate From Diameter (d)

Diameter (d): The distance across the circle, passing through the center. Formula: d = 2 × r.

Calculate From Circumference (C)

Circumference (C): The total distance around the circle’s edge. Formula: C = 2 × π × r or C = π × d.

Calculate From Area (A)

Area (A): The space enclosed within the circle. Formula: A = π × r².

What is a Circle?

A circle is a perfectly round shape where every point on its edge is equidistant from the center. Understanding the different properties of a circle—like its radius, diameter, circumference, and area—is fundamental in geometry and many real-world applications.

How to Use Our Circle Calculator

  1. Choose What to Calculate: Select the property you want to calculate: radius, diameter, circumference, or area.

  2. Enter Known Values: Input the values you know, such as the radius or diameter, into the calculator.

  3. Click Calculate: Get instant, accurate results for your desired calculation.

Why Use Our Circle Calculator?

Example Calculations

Frequently Asked Questions (FAQ)

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