When to use this calculator
Find each interior angle in a regular polygon. All sides and all interior angles must be equal.
Explore the quadrilateral & polygon calculators for other questions in this topic. For a related calculation, use the Regular Polygon Perimeter Calculator: Find the outline length of a regular polygon.
PUTTING IT INTO PRACTICE
Regular Polygon Interior Angle: 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 |
|---|---|
| Number of sides (integer) | 6 |
| Result | 120 degrees |
- Check the input labels and enter the example values above.
- Apply the relationship: Angle = (n − 2) × 180 ÷ n.
- The result is 120 degrees, rounded for display.
How to interpret your result
All sides and all interior angles must be equal.
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.
How do I use the regular polygon interior angle calculator?
Enter number of 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?
Angle = (n − 2) × 180 ÷ n.
What should I check before using the result?
All sides and all interior angles must be equal.
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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