# Regular Polygon Calculator

> Calculate perimeter, area, apothem, circumradius, and angles from side count and side length.

Page: https://askcalculators.com/calculator/regular-polygon-calculator/
Definition: https://askcalculators.com/calculator/regular-polygon-calculator/definition.json
JSON Schema: https://askcalculators.com/calculator/regular-polygon-calculator/schema.json
Version: 1.0.0
Maintained by: AskCalculators (software project; not a credentialed reviewer)
Qualified review: pending. Automated checks do not establish professional approval.
Page status: Live
Review status: Pending

## Use
Open the calculator page and enter values. Query-string parameters can restore and bookmark a calculation.
Example: https://askcalculators.com/calculator/regular-polygon-calculator/?sides=6&sideLength=5

## Inputs
- sides: Number of sides n; type=number; required; default=6; min=3; max=10000
- sideLength: Side length s; type=number; required; default=5; min=0.000001

## Outputs
- area: Area; format=number; primary
- perimeter: Perimeter; format=number
- apothem: Apothem; format=number
- circumradius: Circumradius; format=number
- interiorAngle: Interior angle; format=number
- exteriorAngle: Exterior angle; format=number

## Formula
area = ns² ÷ [4 tan(π/n)]

## Rules
- Empty optional inputs are undefined, not zero.
- Hidden conditional inputs are ignored.
- Do not invent missing required inputs.