How to use this tool
- Enter a radius.
- Calculate to get diameter, circumference, and area.
Circle Calculator
Calculate diameter, circumference, and area from radius.
Topic: math
Inputs
Results
A simple geometry helper for school, engineering, or quick measurements.
Formula
diameter = 2r, circumference = 2πr, area = πr² Show Calculation Logic
Displays only the relevant calculation/logic function for this tool.
FAQ
What does the Circle Calculator do?
Circle Calculator helps you calculate diameter, circumference, and area from radius.
Is this tool free to use?
Yes. You can use this tool for free directly in your browser.
Are my inputs sent to a server?
Your inputs stay in your browser while using this tool.