Enter the total number of sides of any polygon into the calculator to determine the sum of the interior angles. This calculator can also evaluate the number of sides when given the interior angle.

- Central Angle Calculator
- Coterminal Angle Calculator
- Critical Angle Calculator
- Initial Angle Calculator

## Interior Angle Formula

The following formula can be used to calculate the sum of interior angles of any polygon.

A = (n-2) * 180

- Where A is the sum of all interior angles
- n is the total number of sides of the polygon

To calculate a single interior angle, divide the sum of the interior angles by the number of sides.

## Interior Angle Definition

An interior angle is a measure of the sum of all interior angles of a polygon.

## Interior Angle Example

How to calculate interior angle?

**First, determine the number of sides.**Count the total number of sides of the polygon you are looking at. For example, a square would have 4 sides and a pentagon would have 5 sides.

**Next, calculate the sum.**Determine the total sum of the interior angles using the formula A = (n-2)*180. For example, for a pentagon this would equal (5-2)*180= 3*180 = 540.

## FAQ

**What is an interior angle?**

An interior angle is the measure of the sum of all of the interior angles created by a polygon.