**Instructions:**

- Enter the radius or diameter of the circle.
- Select the measurement system (Metric or Imperial).
- Click "Calculate" to calculate the circle's properties.
- View the chart and details below for results.
- Click "Clear" to reset the form and chart.
- View and copy the calculation history in the table.

A circle calculator is a tool that allows users to calculate various properties of a circle, such as its area, circumference, radius, and diameter. These calculators are used in mathematics, engineering, and other fields where circles are commonly encountered.

**Concepts**

The following are some of the key concepts that underlie circle calculators:

**Circle:**A circle is a two-dimensional shape that consists of all points in a plane that are equidistant from a given point, called the center.**Radius:**The radius of a circle is the distance from the center of the circle to any point on the circle.**Diameter:**The diameter of a circle is the distance across the circle, passing through the center.**Circumference:**The circumference of a circle is the total length of its perimeter.**Area:**The area of a circle is the amount of space that it occupies.

**Formulae**

The following are some of the most common formulae used in circle calculators:

**Circumference:**

```
C = 2πr
```

where:

- C is the circumference of the circle
- π is a mathematical constant with the approximate value of 3.14
- r is the radius of the circle

**Area:**

```
A = πr²
```

where:

- A is the area of the circle
- π is a mathematical constant with the approximate value of 3.14
- r is the radius of the circle

**Diameter:**

```
d = 2r
```

where:

- d is the diameter of the circle
- r is the radius of the circle

**Benefits of using a circle calculator**

There are several benefits to using a circle calculator, including:

**Convenience:**Circle calculators can save users a lot of time and effort, as they can perform complex calculations quickly and accurately.**Accuracy:**Circle calculators are very accurate, as they use sophisticated mathematical algorithms to perform their calculations.**Flexibility:**Circle calculators can be used to calculate a variety of properties of a circle, including its area, circumference, radius, and diameter.**Versatility:**Circle calculators can be used in a variety of fields, including mathematics, engineering, and other fields where circles are commonly encountered.

**Interesting facts about circles**

- The circle is one of the most fundamental shapes in geometry.
- Circles are found in nature in a variety of forms, such as the sun, moon, planets, and stars.
- Circles are also used in many different man-made objects, such as wheels, gears, and coins.
- The largest known circle in the universe is the observable universe, which has a radius of about 46.5 billion light-years.
- The smallest known circle in the universe is the Planck length, which is the smallest possible distance in space and has a radius of about 1.616 × 10⁻³⁵ meters.

**Conclusion**

Circle calculators are a valuable tool for anyone who needs to calculate the properties of circles. They are convenient, accurate, flexible, and versatile. Circle calculators are used in a variety of fields, including mathematics, engineering, and other fields where circles are commonly encountered.

## Additional information

### Other types of circle calculators

In addition to the basic circle calculator described above, there are also a number of more specialized circle calculators available. These calculators can be used to calculate more complex properties of circles, such as the area of a sector, the length of an arc, and the volume of a sphere.

## Applications of circle calculators

Circle calculators are used in a variety of applications, including:

**Engineering:**Circle calculators are used by engineers to design a variety of objects, such as wheels, gears, and pipes.**Mathematics:**Circle calculators are used by mathematicians to study the properties of circles and other geometric shapes.**Construction:**Circle calculators are used by construction workers to lay out circular structures, such as foundations and roofs.**Manufacturing:**Circle calculators are used by manufacturers to produce circular objects, such as coins, bearings, and lenses.**Education:**Circle calculators are used by students and teachers in mathematics and other science classes

**References**

**Euclid:**Elements, Book I, Proposition 1**Archimedes:**On the Circle, Proposition 1**Isaac Newton:**Principia Mathematica, Book III, Proposition 7**Leonhard Euler:**Introductio in Analysin Infinitorum, Volume I, Chapter 4**Carl Friedrich Gauss:**Disquisitiones Generales circa Superficies Curvas, Chapter 3