**Calculate the area of the circle** online is a simple operation thanks to our calculator, a perfect tool in case we do not remember the formula involving the PI number.

If you want to refresh your memory for the next time you have to calculate the area of a circle, you should know that you have to square the value of its radius and multiply the result by the number PI, it's that easy. You can also skip the operation and use our **online calculator**.

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## Formula to calculate the area of the circle

If you want to know** how to calculate the area of a circle from its radius**below you have it:

Area = πr

^{2}

If you do not remember what is the value of PIyou can use 3.14 to simplify the operation.

For example, we will** calculate the area of a circle** whose radius is 6 centimeters. Taking into account the above formula we are left with the following:

Area of circumference = 3.14 x 6

^{2}= 113.04 cm^{2}

Undoubtedly, this is the simplest exercise that can be proposed to us and that really does not involve any type of difficulty other than remembering **what is the formula for the area of the circumference?**.

## Calculate area of circle with diameter

If we get the diameter, **the radius is obtained by dividing its length by 2**. That is to say:

radius = diameter / 2

In this way **we already have 'r' and we can apply the formula** as described in the previous point.

## What if they give us the perimeter or length?

We have another example of an exercise in which we may be asked for **Calculate the area of the circle from its perimeter or length.**. In this case, the first thing we have to do is to calculate how much is the radius from the perimeter. To do this, we apply the following formula:

radius = perimeter / 2π

And once we have the radius, we can apply the **formula for calculating the area of a circle** you have in the first point of theory.

If you have any questions about this, do not hesitate to leave us a comment and we will be happy to help you.