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Dodecagon Area Calculator.

Calculate the area, perimeter, and apothem of a regular dodecagon.

On-device calculationNo signup
01

Set your values

Results update as you type.

area: 279.903811 units²

area

279.903811units²
perimeter: 60

perimeter

60
apothem: 9.330127

apothem

9.330127

Results update automatically as you type.

Use Cases

Geometry and Design

Useful for calculating the area and dimensions of dodecagonal shapes in architecture, tiling, or crafts, such as designing a dodecagonal table or garden bed.

Example: If you have a dodecagonal tile with side 5 cm, find its area to estimate material needed.

Educational Exercises

Helps students verify their manual calculations of dodecagon properties in math homework or exam preparation.

Example: Check the area of a dodecagon with side 10 units.

Frequently Asked Questions

What is a regular dodecagon?
A regular dodecagon is a 12-sided polygon where all sides and angles are equal. Each interior angle is 150 degrees, and it has 12 lines of symmetry.
How is the area of a regular dodecagon calculated?
The area is calculated using the formula: Area = 3 * (2 + √3) * side². This formula comes from dividing the dodecagon into 12 congruent isosceles triangles and summing their areas.
What is the apothem of a dodecagon?
The apothem is the distance from the center to the midpoint of any side. For a regular dodecagon with side length 'a', the apothem is given by a * (2 + √3) / 2. It is also the radius of the inscribed circle.

Tips & Common Mistakes

Tips

  • Ensure the side length is positive; otherwise, the calculator will not produce valid results.
  • You can use any unit (e.g., cm, m, inches) as long as you are consistent; the area will be in square units, and perimeter/apothem in the same unit.
  • For quick estimates, remember that the area is approximately 11.196 times the square of the side length.
  • If you need the circumradius (radius of circumscribed circle), it is not provided here, but you can derive it from the side length using the formula R = a / (2 * sin(π/12)).

Common Mistakes to Avoid

  • Using the side length in different units for different fields – always use the same unit for all inputs.
  • Confusing the apothem with the circumradius; the apothem is smaller and is the distance to a side, not a vertex.
  • Forgetting that the formula applies only to regular dodecagons (all sides equal); irregular dodecagons require different methods.

Last updated: August 13, 2026