Area of a Circle Calculator
⬛ Area & perimeter (2D). Use the Area of a circle formula to find area, radius: pick the value you want, type the others, and the answer updates as you go.
Area78.54 cm²
Pick the ○ next to the value you want to find, fill in the others, and it solves as you type.
What each letter means
| Quantity | Unit |
|---|---|
| Area | cm² |
| Radius | cm |
Worked example
Find the area when Radius = 5 cm.
Using A = π r²: Area = 78.54 cm².
Frequently asked questions
What is the formula for Area of a circle?
A = π r².
What do the letters stand for, and what units are used?
Area in cm², Radius in cm.
How do you calculate area?
Put the values into A = π r². For example, with Radius = 5 cm, area = 78.54 cm².
Can I solve for a different value?
Yes. In the calculator above, pick the circle next to any value (area, radius) and fill in the others: it rearranges the formula for you.
