Any InputVisual Circle100% Private
r

Radius

5.000000

Diameter

10.000000

Circumference

31.415927

Area

78.539816

Formulas:

Circumference = 2 x pi x r

Area = pi x r squared

FAQ

What formulas are used?
Circumference = 2 x pi x radius. Area = pi x radius squared. Diameter = 2 x radius.
Can I input any measurement?
Yes. Enter radius, diameter, circumference, or area — the tool calculates all other values automatically.
What value of pi is used?
The tool uses the full JavaScript Math.PI constant (3.141592653589793) for maximum precision.
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About Circle Calc

What this tool does

General-purpose calculators cover percentages, dates, time differences, BMI, tips, taxes, salaries, loans, compound interest, and dozens of everyday math problems. Results are computed instantly in the browser.

Why use this tool

Quick calculations come up constantly: splitting a bill, figuring out how many days until a deadline, converting an hourly rate to an annual salary. Having a purpose-built calculator is faster and less error-prone than a spreadsheet.

How it works

Each calculator applies the relevant mathematical formula to your inputs. Financial calculators use standard amortization and compound-interest equations. Date calculators leverage JavaScript's Date object with timezone-aware arithmetic.

Pro tip

For loan and mortgage calculations, small changes in interest rate matter more than you think. Try adjusting the rate by 0.25% to see how it affects total interest paid over the life of the loan.

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