This regular polygon calculator can help you calculate the area, perimeter, interior angle, central/exterior angle, apothem and the radius of circumcircle if you provide the number of sides and the side length.

Number of sides:*
Side length:*

## What is a regular polygon?

A regular polygon is defined as a two-dimensional shape with all sides equal (equilateral) and all angles equal (equiangular). This is the list with most often referred to regular polygons:

 Regular Polygon Name No. of sides (n) Interior angle (x) Exterior angle (y) equilateral triangle (trigon) 3 (π/3) = 60° (2π/3) = 120° square (tetragon) 4 (2π/4) = 90° (2π/4) = 90° pentagon 5 (3π/5) = 108° (2π/5) = 72° hexagon 6 (4π /6) = 120° (2π/6) = 60° heptagon 7 (5π/7) = 128.57° (2π/7) = 51.43° octagon 8 (6π/8) = 135° (2π/8) = 45° nonagon 9 (7π/9) = 140° (2π/9) = 40° decagon 10 (8π/10) = 144° (2/10)π = 36° undecagon 11 (9π/11) = 147.27° (2π/11) = 32.73° dodecagon 12 (10π/12) = 150° (2π/12) = 30°

## How does this regular polygon calculator work?

The algorithm behind this regular polygon calculator requires the side length and the number of sides to be given, while it is based on the formulas provided below:

r = (s/2)*cotangent(180°/n)

R = (s/2)*cosecant(180°/n)

Area = (Perimeter*r)/2

Perimeter = n*s

Interior angle (x) = [(n-2)/n]*180°

Sum of interior angles = (n-2)*180°

Exterior angle (y) = 360°/n

Where:

n = number of sides

s = side length

r = apothem (radius of inscribed circle)