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Circle Calculator

Calculate area and circumference

Input Parameters

Configure the system requirements below.

Computes area, circumference, and diameter based on π (3.14159...)
Instructions & Terms

What is a Circle Calculator?

A circle calculator computes area, circumference, diameter, and other properties of a circle from any known measurement (radius, diameter, or circumference).

How to Use This Calculator

Enter radius, diameter, or circumference. The calculator automatically computes all other values.

Circle Formulas

  • Area: πr²
  • Circumference: 2πr or πd
  • Diameter: 2r

Uses

  • Construction projects
  • Land measurement
  • Engineering
  • Everyday calculations

FAQ

What is π (pi)?
Pi ≈ 3.14159. It's the ratio of circumference to diameter.