Perimeter of a Polygon Calculator

A polygon is a closed two-dimensional figure bounded by straight line segments. For a regular polygon—where all interior angles and side lengths are equal—finding the perimeter is straightforward. The calculator uses the fundamental formula: Perimeter = n × s, where 'n' represents the total number of sides and 's' stands for the length of side a. If you know the total perimeter and the number of sides, the tool can also reverse the equation to solve for the individual side length by dividing the perimeter by the number of sides.

Imagine you are designing a hexagonal garden bed and need to know how many landscape edging bricks to buy. A regular hexagon has 6 equal sides (n = 6). Suppose each individual side measures 4.5 meters (side a = 4.5). Applying our formula, Perimeter = 6 × 4.5. Multiplying these values together gives a total perimeter of 27 meters. Thus, you will need 27 linear meters of edging material to enclose the garden completely.

Always verify that your polygon is regular before applying the standard multiplication formula, as irregular shapes require summing every unique side individually. Ensure that all measurements use the same unit of length—convert centimeters to meters, for instance, before performing the calculation to avoid scaling errors. Double-check your input values for the number of sides, remembering that a polygon must have at least three sides to form a closed shape.