Circle Area Calculator - Enter radius and calculate the circle area

Area of Circle Formula
Formula to calculate Area of a Circle using Radius
Area = πr²
r is radius and Pi value is 3.14

Find the Radius of a Circle for a given Area
Radius = square root (A / π)
A is area and Pi value is 3.14
Formula to calculate Perimeter of a Circle using Radius
Perimeter = 2πr
r is radius and Pi value is 3.14

Find the Radius of a Circle for a given Perimeter
Radius = square root (C / 2π)
C is Circumference or Perimeter and Pi value is 3.14
Area of Sector Formula
Formula to calculate Area of a Sector
Area =(θ/360°) x πr²
r is radius, Pi value is 3.14 and 𝜃 is the angle of the sector.
Formula to calculate Perimeter of a Sector
Perimeter = 2r + ((θ/360) × 2πr )
r is radius, Pi value is 3.14 and 𝜃 is the angle of the sector.
Area of Oval Formula
Area of Oval Formula
Area = π(A + B)/2
A is Major Axis, B is Minor Axis and Pi value is 3.14

Formula for Perimeter of a Oval
Perimeter = 2π square root((A² + B²)/2)
A is Major Axis, B is Minor Axis and Pi value is 3.14
Area of Ellipse Formula
Area of Ellipse Formula
Area = πAB
A is Major Axis, B is Minor Axis and Pi value is 3.14

Formula for Perimeter of a Ellipse
Perimeter = π (A + B) (1 + 3h / 10 +square root( 4 - 3h))
A is Major Axis, B is Minor Axis , h is (A - B)² / (A + B )² and Pi value is 3.14
Area of Rhombus Formula
Formula to calculate Area of a Rhombus
Area = PQ / 2
P is Diagonal 1 and Q is Diagonal 2

Find the Perimeter of a Rhombus for a given Diagonal Value
Radius = 2 * square root (P² + Q²)/2
P is Diagonal 1 and Q is Diagonal 2
Area of a Parallelogram Formula
Area of a Parallelogram
Area = ( b*h)
h is height and b is base

Perimeter of a Parallelogram
Perimeter = 2(a + b)
a and b are the length of two adjacent sides of parallelogram
Area of a Square Formula
Formula to calculate Area of a Square using side
Area = a²
a is side

Find the side of a Square for a given area
Side = Square Root (A)
A is area
Formula to calculate Perimeter of a Square using side
Perimeter = 4a
a is side
Find the side of a Square for a given area
Side = P / 4
P is Perimeter
Area of a Rectangle Formula
Formula to calculate Area of a Rectangle using Length and Width
Area = L * W
L is Length and W is Width

Formula to calculate Perimeter of a Rectangle using Length and Width
Perimeter = 2 * (L + W)
L is Length and W is Width
Triangle Area Formula
Formula to calculate Area of a Equilateral Triangle using Side
Area = square root (3)/4 a²
a is side

Formula to calculate Area of a Isosceles Triangle using Base and Height
h = square root (a² - b²/4)
Area = bh
b is base and h is Height

Formula to calculate Area of a Scalene Triangle using Side
S = a + b + c / 2
Area = square root (s (s-a) (s-b) (s-c))
a, b and c are sides

Formula to calculate Perimeter of a Equilateral Triangle using Side
Perimeter = 3a
a is side

Formula to calculate Perimeter of a Isosceles Triangle using base and side
Perimeter = 2a + b
b is base and a is side

Formula to calculate Perimeter of a Scalene Triangle using Base and Height
Perimeter = a + b + c
a, b and c are sides

Trapezoid Area Formula
Formula to calculate Area of a Trapezoid using Axes and Height
Area = 1/2 (a + b) h
a and b are axes and h is height

Formula to calculate Perimeter of a Trapezoid using Axes and Height
Perimeter = (a + h + b + h)
a and b are axes and h is height
Pentagon Area Formula
Formula to calculate Area of a Pentagon using Side
Area = 1/4 square root(5 (5 + 2 square root(5)))a²
A is Side

Formula to calculate Perimeter of a Pentagon using Side
Perimeter = 5a
a is Side
Hexagon Area Formula
Area of a Hexagon
Area = 3 * square root (3) /2 a²
a is side

Perimeter of a Hexagon
Perimeter = 6a
a is side
Octagon Area Formula
Formula to calculate Area of a Octagon using Side
Area = 2(1 + square root (2))a²
a is Side

Formula to calculate Perimeter of a Octagon using Side
Perimeter = 8a
a is Side
Kite Area Formula
Formula to calculate Area of a Kite using Diagonals
Area = ab/2
a is diagonal 1 and b is diagonal 2

Formula to calculate Perimeter of a Kite using Diagonals
Perimeter = 2(a + b)
a is diagonal 1 and b is diagonal 2
Frequently Asked Questions on Area Calculator and Area Formula

Area of a circle is πr² where r is radius and Pi value is 3.14
Area of a circle is πr² where r is radius and Pi value is 3.14
Area of triangle is square root (3)/4 a² where a is side.
Area of triangle is square root (3)/4 a² where a is side.
Area of rectangle is L * W where L is Length and W is Width
Area of rectangle is L * W where L is Length and W is Width
Area of a trapezoid is 1/2 (a + b) h where a and b are axes and h is height
Area of a trapezoid is 1/2 (a + b) h where a and b are axes and h is height
Area of scalene triangle is bh where b is base and h is Height
Area of scalene triangle is bh where b is base and h is Height
Area of square is a² where a is side
Area of square is a² where a is side
Area of parallelogram is b*h where h is height and b is base
Area of parallelogram is b*h where h is height and b is base
Diameter = 2 × r where r is radius
Diameter = 2 × r where r is radius
Area of triangle is square root (3)/4 a² where a is side
Area of triangle is square root (3)/4 a² where a is side
Perimeter of rectangle is 2 * (L + W) where L is Length and W is Width
Perimeter of rectangle is 2 * (L + W) where L is Length and W is Width
Perimeter of circle is 2πr where r is radius and Pi value is 3.14
Perimeter of circle is 2πr where r is radius and Pi value is 3.14
Area of rectangle is L * W where L is Length and W is Width
Area of rectangle is L * W where L is Length and W is Width
Area of sphere is 4πr² where r is radius and Pi value is 3.14
Area of sphere is 4πr² where r is radius and Pi value is 3.14
Area of equilateral triangle is square root (3)/4 a² where a is side
Area of equilateral triangle is square root (3)/4 a² where a is side
Area of rhombus is PQ / 2 where P is Diagonal 1 and Q is Diagonal 2
Area of rhombus is PQ / 2 where P is Diagonal 1 and Q is Diagonal 2
Area of a right triangle is ab/2 where a and b are sides
Area of a right triangle is ab/2 where a and b are sides
Perimeter of square is 4a where a is side
Perimeter of square is 4a where a is side
Area of sector (θ/360°) x πr² where r is radius, Pi value is 3.14 and 𝜃 is the angle of the sector.
Area of sector (θ/360°) x πr² where r is radius, Pi value is 3.14 and 𝜃 is the angle of the sector.
Area of hexagon is 3 * square root (3)/2 a² where a is side
Area of hexagon is 3 * square root (3)/2 a² where a is side
Area of semicircle is 1/2 πr² where r is radius and Pi value is 3.14
Area of semicircle is 1/2 πr² where r is radius and Pi value is 3.14
Area of parallelogram is b * h where h is height and b is base
Area of parallelogram is b * h where h is height and b is base
Area of sector is (θ/360°) x πr² where r is radius, Pi value is 3.14 and 𝜃 is the angle of the sector.
Area of sector is (θ/360°) x πr² where r is radius, Pi value is 3.14 and 𝜃 is the angle of the sector.
Area of Isosceles triangle is bh where b is base and h is Height
Area of Isosceles triangle is bh where b is base and h is Height
Area of polygon is 1/2 ap where a is apothem and p is perimeter
Area of polygon is 1/2 ap where a is apothem and p is perimeter
Area of kite is ab/2 where a is diagonal 1 and b is diagonal 2
Area of kite is ab/2 where a is diagonal 1 and b is diagonal 2
Area of ellipse is πAB where A is Major Axis, B is Minor Axis and Pi value is 3.14
Area of ellipse is πAB where A is Major Axis, B is Minor Axis and Pi value is 3.14
Area of octagon is 2(1 + square root (2))a² where a is Side
Area of octagon is 2(1 + square root (2))a² where a is Side