When to use this calculator
Find the sum of all interior angles in a simple polygon. Applies to a simple planar polygon, including non-regular polygons.
Explore the quadrilateral & polygon calculators for other questions in this topic. For a related calculation, use the Rectangle Area Calculator: Find the area of a rectangle from its length and width.
PUTTING IT INTO PRACTICE
Polygon Interior Angle Sum: a worked example
The values below are an illustrative example, not a recommendation. Replace them with measurements or assumptions that match your question.
| Input | Example value |
|---|---|
| Sides (integer) | 6 |
| Result | 720 degrees |
- Check the input labels and enter the example values above.
- Apply the relationship: Interior angle sum = (n−2) × 180°.
- The result is 720 degrees, rounded for display.
How to interpret your result
Applies to a simple planar polygon, including non-regular polygons.
A perimeter measures the outline; area measures the enclosed surface. Regular polygon tools assume equal sides and angles. For a parallelogram or trapezoid, use the height perpendicular to the selected base.
Frequently asked questions
What does regular polygon mean?
It is a polygon with all sides equal and all interior angles equal.
When is the polygon interior angle sum calculator useful?
Find the sum of all interior angles in a simple polygon. Applies to a simple planar polygon, including non-regular polygons.
How do I use the polygon interior angle sum calculator?
Enter sides (integer). The result updates automatically. Use the units shown beside each input; the example values illustrate the method.
Which formula does this calculator use?
Interior angle sum = (n−2) × 180°.
What should I check before using the result?
Applies to a simple planar polygon, including non-regular polygons.
How are results rounded?
Scalar numbers display up to six decimal places, with scientific notation for very large or small values. Text, fraction, date and schedule outputs use the format described on the tool. Intermediate calculations use JavaScript floating-point arithmetic. Keep sensible precision for your measurements.
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