When to use this calculator
One side determines a regular polygon’s apothem and therefore its area. Irregular polygons need a different method.
Explore the quadrilateral & polygon calculators for other questions in this topic. For a related calculation, use the Regular Polygon Exterior Angle Calculator: Find the equal exterior turning angle of a regular polygon.
PUTTING IT INTO PRACTICE
Regular Polygon Area: 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) | 4 |
| Side length | 5 |
| Result | 25 square units |
- Check the input labels and enter the example values above.
- Apply the relationship: Area = n × side² ÷ (4 tan(π/n)).
- The result is 25 square units, rounded for display.
How to interpret your result
All sides and 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.
When is the regular polygon area calculator useful?
One side determines a regular polygon’s apothem and therefore its area. Irregular polygons need a different method.
How do I use the regular polygon area calculator?
Enter number of sides (integer), side length. The result updates automatically. Use the units shown beside each input; the example values illustrate the method.
Which formula does this calculator use?
Area = n × side² ÷ (4 tan(π/n)).
What should I check before using the result?
All sides and 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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