Math
Circle Area Calculator
Find the area inside a circle from its radius.
This result is the area inside the circle, so a larger radius gives a much larger area because the radius is squared.
Formula
Circle area = π × radius squared.
How it works
Enter the radius, the distance from the centre to the edge. The calculator squares it and multiplies by pi.
Worked example
For example, a radius of 5 gives π × 5 × 5 = 78.5398 square units.
FAQs
What does the Circle Area do?
It takes the values you enter and works out the circle area for you, showing the result straight away.
What should I enter?
Enter ordinary numbers in the boxes above. If a value does not make sense for this calculation, the page will ask you to check it instead of showing a wrong answer.
Can I use the result for homework or everyday math?
Yes. It is a general-purpose math helper; for exam or professional work, still check the steps against your own working.
Related calculators
Arithmetic Sequence Calculator
Circle Circumference Calculator
Instant result, no sign-up.
All tools are free.
Each page shows the formula it uses, so you can check the result yourself.
Built for phone browsers.
Start with a free calculator
Search, pick a calculator, and get an instant result. No sign-up, no download.