Area of a Circle Calculator

The area of a circle calculator helps you to calculate the area of a circle with the diameter, radius and circumference of a circle.

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Area of a Circle

The area of a circle is defined as the amount of space it takes to completely surround the circle. It is calculated by the equation A = πr2, where A is the area, r is the radius, and π is the constant pi (approximately 3.14159).

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Area of a Circle formula

The formula for the area of a circle is:

Based onArea of Circle
RadiusA = π(r)² = π(radius)²
DiameterA = π(D/2)² = π(dimater/2)²
CircumferenceA = C²/4π = circumference²/4π


Example.1:-The radius of a circle is 10 cm, find its area of a circle.

Answer:- Area = πr² = 22/7 * (10)² = 314.15 cm².

Example. 2 The circumference of a circle is 20 cm, find its circle area.

Answer:- Circumference of circle = 2πr = 20 cm

radius = 10/π

Area = πr² = π * (10/ π)² = 100/π = 31.83 cm².

Example.3:-The diameter of a circle is 20cm, find its area.

Answer:- diameter = radius/2 ⇨ radius = diameter/2 = 20/2 = 10 cm.

Area = πr² = π * (10)² = 314.15 cm².


What is the area based on diameter?

Divide the diameter by 2 to obtain the radius of the circle. Then, square the radius and multiply it by π to calculate the area.
Area = π(diamter/2)²
where, π (pi) = 3.14159.

What is the area of a 20mm diameter circle

To calculate the area of a circle with a 20 mm diameter, you can use the formula
Area = π * (diameter/2)²
Let’s calculate it step by step:
Radius = diameter/2 = 20 mm / 2 = 10 mm
Area = π * (10 mm)²
Area ≈ 3.14159 * 100 mm²
Area ≈ 314.159 mm²
Therefore, the area of a circle with a 20 mm diameter is approximately 314.159 square millimetres.

How to use the area of a circle calculator

First select the three options of circle- radius, diameter and circumference of a circle then enter the value and select unit then click the calculate button you get an answer in the area of a circle

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