Math

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Regular Polygon Calculator.

Calculate area, perimeter, and apothem for a regular polygon.

On-device calculationNo signup
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Set your values

Results update as you type.

Results update automatically as you type.

Use Cases

Geometry homework and study

Quickly verify area, perimeter, and radius values for regular polygons in math assignments or exam prep.

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

Design and construction planning

Determine dimensions for regular polygon-shaped objects, such as tiles, garden beds, or architectural elements.

Example: Find the circumradius of a regular octagon with side length 2 meters.

Frequently Asked Questions

What is a regular polygon?
A regular polygon is a polygon with all sides and all interior angles equal. Examples include equilateral triangles, squares, and regular pentagons. This calculator uses the number of sides and side length to compute its properties.
What results does this calculator provide?
Based on the number of sides and side length, it calculates the area, perimeter, inradius (apothem), circumradius, and other geometric properties of the regular polygon. All results are computed deterministically from the given inputs.
Can I use this calculator for any number of sides?
Yes, you can enter any positive integer for the number of sides. The calculator will compute the corresponding properties for that regular polygon, provided the side length is also positive.

Tips & Common Mistakes

Tips

  • Ensure the number of sides is at least 3, as a polygon must have three or more sides.
  • Use consistent units for side length; all results will be in those units (or square units for area).
  • For very large numbers of sides, the polygon approaches a circle; results will reflect that trend.
  • Double-check your inputs: a small change in side length can significantly affect area and radius values.

Common Mistakes to Avoid

  • Entering a side length of zero or a negative number, which is invalid for a polygon.
  • Using the number of sides as the side length, or vice versa, leading to incorrect calculations.
  • Assuming the calculator uses degrees for angles; it uses the number of sides and side length directly, not angles.

Last updated: August 13, 2026