Math Calculators

Circle Calculator

Find circle area and circumference. The estimate updates in your browser as you type.

Area 78.54 sq units

Circumference: 31.416.

Local estimate.

What this tool is for

Circle Calculator is built for math checking inside math calculators when you need to calculates circle area from radius. It focuses on circle instead of making you adapt a broad calculator to a narrow task.

When to use it

Use it when radius are already known and you want a fast estimate before comparing options, checking a worksheet, or copying the result into another workflow.

Inputs

  • Radius is one of the direct inputs used to calculate circle.

Formula

area = pi x radius^2

Example

Radius 5 gives area about 78.54.

What the result means

The result labeled "Circle" is the direct output of area = pi x radius^2. In the worked example, radius 5 gives area about 78.54.

Before you rely on the result

Check the inputs and formula before using the result in homework, engineering, finance, or scientific work.