Cylinder Surface Area Calculator
Closed cylinder surface area = 2 × π × radius × (radius + height).
Open toolCircle Area Calculator
Area = π × radius². Use one consistent length unit for every dimension.
Free to useNo sign-upRuns in your browser
Enter your details
Enter the inputs, then select Calculate result.
Your result
Enter your details
Result will appear here
How Circle Area Calculator works
Area = π × radius².
Use one consistent length unit for every dimension. Results are in the corresponding squared or cubed unit. Dimensions must be positive. Finite real numbers only. Display uses up to 12 significant digits; binary floating-point arithmetic can introduce rounding.
How to use Circle Area Calculator
Follow the labelled inputs.
Enter radius
Replace the example with radius. The field labels specify the expected format and units.
Input and settings
Check the remaining inputs
This tool uses one input. Check the supported range before running it. Use one consistent length unit for every dimension.
Tool result
Run, review and save
Select Calculate result. Review the calculated result, then copy it or download the result text.
Review the details
Examples and uses for Circle Area Calculator
Check the supplied example
The starting example produces 28.2743338823. Area = π × radius².
Use your own inputs
Read the labels for radius. Use one consistent length unit for every dimension.
Record a reviewed result
Copy the calculated result into your notes. Keep the formula and assumptions with it if someone else needs to reproduce the calculation.
How to read the result
Read the units and assumptions with the output.
Area = π × radius².
Use one consistent length unit for every dimension. Results are in the corresponding squared or cubed unit. Dimensions must be positive. Finite real numbers only. Display uses up to 12 significant digits; binary floating-point arithmetic can introduce rounding.
Supported input and limits
Check the stated scope before you run it.
Use one consistent length unit for every dimension. Results are in the corresponding squared or cubed unit. Dimensions must be positive. Finite real numbers only. Display uses up to 12 significant digits; binary floating-point arithmetic can introduce rounding.
The input stays in this browser. Copy result and Download save the same displayed text.
More free tools to try
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Regular Polygon Area Calculator
Regular polygon area = n × side² / (4 × tan(π/n)).
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Sector Area Calculator
Sector area = angle / 360 × π × radius².
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Sphere Surface Area Calculator
Sphere surface area = 4 × π × radius².
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Trapezoid Area Calculator
Trapezoid area = (parallel side a + parallel side b) × height / 2.
Open toolCircle Area Calculator: common questions
Answers about using Circle Area Calculator and understanding its results.
Which inputs does this tool accept?
Use one consistent length unit for every dimension. Results are in the corresponding squared or cubed unit. Dimensions must be positive. Finite real numbers only. Display uses up to 12 significant digits; binary floating-point arithmetic can introduce rounding.
Can I copy or download the result?
Yes. Copy result copies the displayed text, and Download saves the same result as a text file. Calculations run in your browser without an account.
Calculate result with your input
Check the calculated result, then copy or download it.