In geometry, we will study about polygons. We have many kinds of polygons. Any geometry shape which is enclosed by its sides is called as polygon.  A regular Octagon is eight sided polygon. The regular Octagon has eight equal sides and eight equal internal angles and eight equal external angles. 


  • Internal angle of a regular Octagon is 135°.
  • External angle of a regular Octagon is 45°.
  • Sum of internal angles of regular Octagon is 1050°.
  • Sum of external angles of regular Octagon is 360°.
Octagon Calculator is a mathematical tool which will help us to calculate the area and perimeter of any given regular octagon.
The space inside octagon boundary is known as the area of an octagon. It is measured in square units. With known side length $a$ the area of an octagon can be calculated using the following formula  

Area of a octagon = $2 a^{2}(1+\sqrt{2})$ 

Perimeter of the octagon is a path that surrounds the area. The perimeter of an octagon can be obtained by the formula 

Perimeter = $8 \times a$