Circle Circumference Calculator

Last updated: Math Calculators

Circle Circumference Calculator

Please provide a radius or diameter below to calculate the circumference of a circle

About This Calculator

This calculator computes the circumference of a circle using either the radius or diameter. You can also enter a custom value of π if needed.

How It Works

  1. Enter either the radius or diameter of the circle. The other value will be auto-filled.
  2. Optionally, you can provide a custom value for π (default is 3.14159).
  3. Click "Calculate" to get the circumference along with the calculation steps.
Circumference = 2 × π × r
or
Circumference = π × d

Frequently Asked Questions

Can I enter either radius or diameter?

Yes, you can enter either one and the other will be calculated automatically.

What if I want to use π = 3.14?

You can override the default π value by typing 3.14 or any number you prefer into the input box.