# Area of a Circle Calculator

By Łucja Zaborowska, MD
Last updated: Oct 13, 2020

The area of a circle calculator helps you compute the surface of a circle given a diameter or radius. Our tool works both ways - no matter if you're looking for an area to radius calculator or a radius to the area one, you've found the right place

We'll give you a tour of the most essential pieces of information regarding the area of a circle, its diameter, and its radius. We'll learn how to find the area of a circle, talk about the area of a circle formula, and discuss the other branches of mathematics that use the very same equation.

## How to calculate the area of a circle? Area of a circle formula

So, let's see how to find the area of a circle. There are several ways to achieve it. Here, we can calculate the area of a circle using a diameter or using a radius.

 💡 The diameter is the line that crosses the center of the figure and touches both of its margins. The radius begins at the center of the figure and ends at the figure's margin.

You can find diameter of a circle by multiplying the radius of a circle by two:

`Diameter = 2 * Radius`

Area of a circle radius. The radius of a circle calculator uses the following area of a circle formula:

`Area of a circle = π * r2`

Area of a circle diameter. The diameter of a circle calculator uses the following equation:

`Area of a circle = π * (d/2)2`

Where:

• π is approximately equal to 3.14. It doesn't matter whether you want to find the area of a circle using diameter or radius - you'll need to use this constant in almost every case.

Now that you know how to calculate the area of a circle, we encourage you to try our other circle calculators: >A sector of a circle is section of a circle between two radii. You can think of it as a giant slice of pizza. >It's a "cut-off" part of a circle, limited by a chord or a secant. >It's an angle with the vertex in the center, whose arms extend to the circumference.

## How to use the area of a circle calculator? Diameter to area and radius to area. You can easily calculate everything, the area of a circle, its diameter, and its radius, using our area of a circle calculator in a blink of an eye:

1. Determine whether your given value is a diameter or a radius using the picture on the right and definitions available in the section above (you can calculate area of a circle using diameter as well as radius).

2. Enter your value into the proper field of the calculator.

3. It didn't take long - your results are here! We decided to include the step-by-step solution and all the most important data right below the calculator.

That is how to calculate the area of a circle in no time 😉

## Why do we need the surface area of a circle calculators?

The circle's area found with both the radius and diameter calculators serves as a base for many other equations - not only in mathematics but also in everyday life! Here are a few examples where knowing how to find the area of a circle might be useful:

• We need to know the surface area of a circle in order to calculate a cone's volume and its surface area 🎉

• Your pizza party wouldn't be complete without our pizza tool based on the diameter to area calculator 🍕

• We use calculations similar to this one when obtaining information about a sphere, such as sphere volume.🌐

• Do you fancy nice dresses? Maybe you love to sew? Discover our circle skirt calculator! Efficient sewing has never been easier. 👗

Łucja Zaborowska, MD in
Diameter (d)
in
Area (A)
in²
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