Area of a Circle Calculator

Welcome to our Area of a Circle Calculator page.

We explain how to find the area of a circle and provide a quick calculator to work it out for you, step-by-step.

There is also a separate calculator which will find the radius and diameter of a circle, if you already know the area.

Area of a Circle Calculator

This calculator finds the area of a circle when the radius or diameter is known.

Area of a Circle Calculator

Answer1


Answer2

 
 

How the Calculator Works

  1. Select if you want to use the radius or diameter (default is radius).
  2. For the value, you can choose a whole number, decimal or fraction.
    • You can type a fraction by typing the numerator then '/' then the denominator.
    • You can type a mixed number by typing the whole-number part, then a space then the fraction part.
    • Examples: 2 1/2 (two and one-half); 3 4/5 (three and four-fifths); 7 1/3 (seven and one-third).
  3. Choose your units of measurement (default is cm)
  4. Choose your desired accuracy (default is 2 decimal places)
  5. Click the Find Area button
  6. You will be given two answers for the area, one in terms of Pi (π) and the other answer as a decimal value.

Area of a Circle Calculator 2

This calculator finds the radius and diameter of the circle when the area is known.

Area of a Circle Calculator 2

Answer1


Answer2

 
 

How the Calculator Works

  1. Choose the area value: you can choose a whole number, decimal or fraction.
  2. Choose your units of measurement (default is none)
  3. Choose your desired accuracy (default is 2 decimal places)
  4. Click the Find Radius button
  5. You will be shown the radius and diameter of the circle as a decimal to the required accuracy.

Area of a Circle Formula

area of a circle formula image

The formula for the area of a circle is: A = πr2, where r is the radius of the circle.

How to Find the Area of a Circle Support

We hope that our calculator provides with useful step-by-step instructions for finding the area of a circle.

If you would like some more help and support try our Area of a Circle support page.

There are lots of worked examples, as well as worksheets, word problems and even an online quiz.

More Recommended Math Worksheets

Take a look at some more of our worksheets similar to these.

More Circle Worksheets and Support Pages

More Area & Volume Calculators

We have a range of area and volume calculators to help you find the area and volumes of a range of different 2d and 3d shapes.

Each calculator page comes with worked examples, formulas and practice worksheets.

More Area Support and Resources

We have a range of other area worksheets and support pages for a range of different 2d shapes.

Parts of a Circle Worksheets and Support

Do you know the special geometric names to describe the different parts of a circle?

Well you can find all the support you need on this page, complete with some practice worksheets and an online quiz!

Looking for more math calculators?

We have a wide range of free math calculators to help you.

Most of our calculators show you their working out so that you can see exactly what they have done to get the answer.

Our calculator hub page contains links to all of our calculators!

 

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