About the Polygon Angle Calculator

Interior and exterior angles, forward and in reverse.

What it is

The Polygon Angle Calculator computes the sum and per-angle interior and exterior angles of any regular polygon from its number of sides, and can also work backwards โ€” given a known interior or exterior angle, it solves for the number of sides, flagging clearly when no whole-sided polygon matches.

Features

Forward mode

Sides to interior and exterior angles, sum and per-angle.

Reverse mode

Angle to number of sides, with validation for non-matching angles.

Polygon naming

Automatic naming from triangle through decagon, then "n-gon".

Diagram

A scaled regular polygon drawn for the current number of sides.

Ready to use it?

Free, no sign-up required.

Open the Polygon Angle Calculator