Math
Regular Polygon Area Calculator
Use this regular polygon area calculator for equal-sided polygons such as pentagons, hexagons, and octagons.
Try an example
Result
Area
—
- Perimeter
- —
- Apothem
- —
Student quick launch
Grade planning, algebra checks, and formulas students reach for most.
Study path
Use this calculator with
Follow these when you want the formula behind the answer, a short lesson, or nearby tools in the same topic.
What the regular polygon area calculator solves
Use this regular polygon area calculator for equal-sided polygons such as pentagons, hexagons, and octagons.
Formula
How to use it
- Enter the number of equal sides.
- Enter one side length.
- Read perimeter, apothem, and area.
How to read the answer
The formula divides a regular polygon into congruent triangles meeting at the center.
Common mistakes and edge cases
- This only works for regular polygons.
- Use side length, not radius.
- Very large side counts approximate a circle.
Worked examples
Regular hexagon
Area
64.9519
Regular pentagon
Area
21.0758
Frequently asked questions
What is the apothem?+
It is the perpendicular distance from the center to a side.
Can this handle a triangle?+
Yes, an equilateral triangle is a regular polygon with 3 sides.
About this calculator
- Written by
- mathcheck editorial team
- Last reviewed
- May 15, 2026
Method
- Uses the values entered by the user and stable formulas documented on the page.
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Last updated: May 15, 2026