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Regular Polygon Area Calculator.

Calculate a regular polygon's area from side count and side length.

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Set your values

Results update as you type.

Results update automatically as you type.

Use Cases

Geometry homework and math practice

Quickly verify area calculations for regular polygons in school assignments or self-study.

Example: Check the area of a regular hexagon with side length 5 cm.

Design and construction planning

Estimate material needs for regular polygonal shapes in tiling, landscaping, or architecture.

Example: Calculate the area of a regular octagonal gazebo floor with side length 2 meters.

Frequently Asked Questions

How do I use the Regular Polygon Area Calculator?
Enter the number of sides (must be 3 or more) and the length of one side in your chosen units. The calculator will instantly compute the area using the formula: area = (n * s^2) / (4 * tan(π/n)), where n is the number of sides and s is the side length.
What is a regular polygon?
A regular polygon is a polygon with all sides of equal length and all interior angles equal. Examples include equilateral triangles, squares, and regular pentagons. This calculator works for any regular polygon with 3 or more sides.
Can I use this calculator for irregular polygons?
No, this calculator is specifically for regular polygons. For irregular polygons, you would need a different method, such as triangulation or using coordinates.

Tips & Common Mistakes

Tips

  • Ensure the number of sides is at least 3; otherwise, the polygon is not valid.
  • Use consistent units for side length to get the area in square units (e.g., if side length is in meters, area is in square meters).
  • For very large numbers of sides, the area approaches that of a circle with the same perimeter, but this calculator remains accurate.

Common Mistakes to Avoid

  • Entering a side length of 0 or negative numbers, which are invalid.
  • Confusing side length with the apothem (distance from center to side midpoint) or radius.
  • Using degrees instead of radians in manual calculations, but this calculator handles it automatically.

Last updated: August 13, 2026