How do I use the Circle Area Calculator?
Enter your values in the fields and the result updates instantly as you type.
Circle Area Calculator
Compute area and circumference of a circle from radius.
e.g., cm, m, ft, in
Results
Formula: Area = pi * r^2, Circumference = 2 * pi * r
Invalid value for this calculator. Please enter valid numbers.
Frequently asked questions
What formula does this calculator use?
Area = pi * r^2, Circumference = 2 * pi * r
Can I use decimal values?
Yes. Decimal inputs are supported for most calculators. Integer-based tools use rounded integer values where appropriate.
Is this calculator free?
Yes. CalcuNimble calculators are free and optimized for fast everyday use.