Polygon Calculator
Calculate the area, perimeter, interior angle, exterior angle, diagonals, apothem and circumradius of a regular polygon using the number of sides and side length.
Enter Polygon Values
Polygon Results
Your polygon results will appear here
Enter the number of sides and side length, then click calculate.
What Is a Polygon Calculator?
A polygon calculator is a geometry tool that helps you calculate important measurements of a regular polygon. A regular polygon has equal side lengths and equal angles, such as a square, pentagon, hexagon or octagon.
This tool is useful for students, designers, engineers, builders and anyone working with geometric shapes. Instead of manually applying several formulas, you only need to enter the number of sides and the side length.
Area & Perimeter
Quickly find the total inside space and outer boundary length of a regular polygon.
Angles
Calculate interior angle, exterior angle and total angle sum without manual work.
Advanced Values
Get diagonals, apothem and circumradius for deeper geometry calculations.
How This Polygon Calculator Works
The calculator uses standard regular polygon formulas. After you enter the side count and side length, it automatically calculates all major values and displays them in a clean result format.
Perimeter = number of sides × side length
Area = n × s² / 4 × tan(π / n)
Interior Angle = (n - 2) × 180 / n
Exterior Angle = 360 / n
Diagonals = n × (n - 3) / 2
Apothem = s / 2 × tan(π / n)
In these formulas, n means the number of sides and s means the length of one side.
Why Use This Tool?
Manual polygon calculations can become confusing when you need more than one value. This calculator saves time by giving you multiple geometry answers from a single input. It is especially helpful when checking homework, planning layouts, comparing shapes or learning polygon formulas.
Polygon Calculator FAQs
What type of polygon does this calculator support?
This calculator is designed for regular polygons. A regular polygon has all sides equal and all angles equal.
Can I calculate the area of a hexagon?
Yes. Enter 6 as the number of sides and add the side length. The tool will calculate the hexagon area, perimeter and other values.
What is the minimum number of sides for a polygon?
A polygon must have at least 3 sides. A three-sided polygon is called a triangle.
What does apothem mean?
The apothem is the distance from the center of a regular polygon to the midpoint of one of its sides.
Is this calculator useful for school geometry?
Yes. It is useful for checking regular polygon formulas, learning angles and verifying area or perimeter answers.