Mini Calculator Logo. Shape Area Calculator

Shape Area Calculator.

Input Shape & Size
Find the area of a
Output Area

Using This Calculator

This calculator can be used to quickly figure the area of a triangle, square, rectangle, circle, sphere, pentagon, hexagon, octogon, cube, or cylinder.

For 2 dimensional shapes it calculates the area of the shape & for 3 dimensional shapes it calculates their surface area.

Area Formulas

The formulas for each regular shape are shown below.


triangle area = base lenght * height / 2


square area = length2


rectangle area = length * width


circle area = π * Radius2


sphere surface area = 4π * Radius2


  • regular pentagon (without apothem): side2 * 1/4* √(5 (5+2 √5))
  • regular pentagon (where apothem is known): area = 5* side * apothem / 2
    • apothem = 1/2 side / tan 36°


hexagon area = side length2 * 3 √3 / 2


octagon area = 2(1+ √ 2) * side length2


cube surface area = 6 * length2


cylinder surface area = 2 π * height * Radius+ 2 π * Radius2

Incircle, Circumcircle, Radius & Apothem

Geometry Circles on a Hexagon.


  • Regular Polygon: A polygon with n sides where all sides have equal lengths.
  • Radius: Line which connects the center of a polygot to one of its verticies.
  • Circumcircle: Circle which fits outside a polygon and connects all verticies. The radius of this circle is the same as the radius of the poligon.
  • Incircle: Circle which fits inside a polygon and connects the midpoint of each side.
  • Apothem: Line connecting the midpoint of a polygon's side to its center.
  • Perimeter: The distance around a polygon. For regular polygons with a fixed number of sides this is found by multiplying the length of a side by how many sides the polygon has.
  • Area: The amount of space inside the boundary of flat 2-dimensional shapes or the surface of a solid 3-dimensional object.