Use this calculator to determine the area of a semicircle. You need to enter the radius of the circle and the angle of rotation or arc in degrees. The angle is required to adjust the calculation based on the part of the circle being considered.
Area of Semi Circle Calculator
What is the Area of a Semicircle?
A semicircle is half of a full circle. The area of a semicircle can be calculated using the radius and the angle.
How to Use the Calculator
To calculate the area, follow these simple steps:

Enter the Radius: Type the radius value into the calculator. For example, enter
6
to find the area of a semicircle with a radius of 6 units. 
Enter the Angle: Input the angle of rotation or arc. For example, enter
180
for a semicircle.
Formula
The formula for the area of a semicircle is:
$A=\pi \times {r}^{2}\times \left(\frac{\theta}{360}\right)$
Variables
Variable  Description 

$A$

Area of the semicircle 
$r$

Radius of the circle 
$\theta $

Angle of rotation (degrees) 
How To calculate Area Of Semicircle
Example 1
Input:
 Radius
$r=4$  Angle
$\theta =180$
Calculation:
Use the formula:
$A=\pi \times {4}^{2}\times \left(\frac{180}{360}\right)$
Calculate the square of the radius:
${4}^{2}=16$
Multiply by π (approximately 3.14):
$16\times 3.14=50.24$
Multiply by the fraction:
$50.24\times \frac{180}{360}=25.12$
Result: The area is approximately 25.12 square units.
Example 2
Input:
 Radius
$r=7$  Angle
$\theta =180$
Calculation:
Apply the formula:
$A=\pi \times {7}^{2}\times \left(\frac{180}{360}\right)$
Calculate the square of the radius:
${7}^{2}=49$
Multiply by π (approximately 3.14):
$49\times 3.14=153.86$
Multiply by the fraction:
$153.86\times \frac{180}{360}=76.93$
Result: The area is approximately 76.93 square units.
FAQs
I hope our calculator helped you find the area of a semicircle easily.