Regular Polygon Calculator
Enter an integer number of sides from 3 to 10,000 and a positive side length.
A QUICK WALKTHROUGH
How to use this tool
- Enter the side count and side length.
- Choose Calculate.
- Review area, perimeter, angles, apothem, and circumradius.
Formulas and units
For n sides of length s: perimeter = ns, apothem = s/(2 tan(π/n)), circumradius = s/(2 sin(π/n)), and area = perimeter × apothem ÷ 2. Angles are shown in degrees.
Validation
The side count must be an integer from 3 through 10,000. The side length must be a finite number greater than zero.
Geometry estimate
Results are mathematical geometry estimates for an ideal regular polygon. Calculations happen locally in your browser.
GOOD TO KNOW
Common questions
What is the apothem?
It is the perpendicular distance from the polygon center to the midpoint of a side.