Circle calculator

Calculate circle calculator with clear inputs and assumptions.

Your inputs stay in your browser. Displayed results are rounded to a maximum of 12 significant digits.

Method and assumptions

Method version 1.0.0 · Updated October 17, 2026

Calculate

Formula: Calculate circle calculator with clear inputs and assumptions.

Calculate circle calculator with clear inputs and assumptions.

Results are estimates where noted and depend on the entered assumptions.

These short examples use the same inputs and core calculation as this tool. Adapt validation and formatting to your application.

JavaScript

const radius = 3;
console.log(Math.PI * radius ** 2, 2 * Math.PI * radius); // area, circumference

TypeScript

const radius = 3;
const area: number = Math.PI * radius ** 2;
const circumference: number = 2 * Math.PI * radius;
console.log(area, circumference);

Python

import math
r = 3
print(math.pi * r**2, 2 * math.pi * r)  # area, circumference

Java

double r = 3;
System.out.println(Math.PI*r*r + ", " + 2*Math.PI*r); // area, circumference

double r = 3;
Console.WriteLine($"{Math.PI*r*r}, {2*Math.PI*r}"); // area, circumference