Perimeter of a Polygon Calculator

Calculate polygon perimeter using side lengths, coordinates, or regular polygon properties

Calculate Polygon Perimeter

Must be 3 or more for a valid polygon

Length of each side (all sides are equal in regular polygons)

Calculation Results

0.00
Perimeter (units)

Formula used: Perimeter = n × a = 6 × 0

Input Validation

⚠️ Side length must be greater than 0

Example Calculations

Regular Octagon

Given: 8 sides, each side = 5 cm

Formula: Perimeter = n × a

Calculation: Perimeter = 8 × 5 = 40 cm

Irregular Quadrilateral

Given: Sides = 3, 4, 5, 6 units

Formula: Perimeter = Σ aᵢ

Calculation: Perimeter = 3 + 4 + 5 + 6 = 18 units

Triangle from Coordinates

Vertices: (0,0), (3,0), (1.5,2.6)

Side 1: √[(3-0)² + (0-0)²] = 3

Side 2: √[(1.5-3)² + (2.6-0)²] = 3

Side 3: √[(0-1.5)² + (0-2.6)²] = 3

Perimeter: 3 + 3 + 3 = 9 units

Common Polygons

Triangle3 sides
Square4 sides
Pentagon5 sides
Hexagon6 sides
Heptagon7 sides
Octagon8 sides
Nonagon9 sides
Decagon10 sides
Dodecagon12 sides

Perimeter Formulas

Regular Polygon

P = n × a

n = sides, a = side length

Irregular Polygon

P = Σ aᵢ

Sum of all side lengths

From Coordinates

P = Σ √[(xᵢ₊₁-xᵢ)² + (yᵢ₊₁-yᵢ)²]

Distance formula

Calculation Tips

Regular polygons have all sides equal

Minimum 3 sides to form a polygon

Coordinates method works for any polygon

Perimeter is always the sum of all sides

Understanding Polygon Perimeter Calculation

What is a Polygon?

A polygon is a closed two-dimensional shape made up of straight line segments. The perimeter is the total distance around the polygon's boundary. Common polygons include triangles (3 sides), squares (4 sides), pentagons (5 sides), and hexagons (6 sides).

Types of Polygons

  • Regular: All sides and angles are equal
  • Irregular: Sides and/or angles are different
  • Convex: All interior angles less than 180°
  • Concave: At least one interior angle greater than 180°

Calculation Methods

Regular Polygon

Simplest method - multiply sides by length

P = n × a

Irregular Polygon

Sum all individual side lengths

P = a₁ + a₂ + ... + aₙ

Coordinate Method

Calculate distances between vertices

P = Σ √[(x₂-x₁)² + (y₂-y₁)²]

Note: The coordinate method is most versatile and works for any polygon shape, including irregular and concave polygons.