`r = "s" /(2* sin(pi/ "n" ))`

Enter a value for all fields

The Radius of a Round Pen calculator computes the radius of a round pen based on the number of panels or post and rail sections (n) and the length of the sides (s). .

INSTRUCTIONS: Choose units and enter the following:

• (n) This is the number of sides in the round pen..
• (s)  This is the length of the sides (panels or rails) of the round pen.

Radius of the Round Pen (r): The calculator returns radius in feet.  However, this can be automatically converted to other length units via the pull-down menu.

General Information

The maximum area that can be fit in a round pen is when the corners are all equal distant from a center point (r).  This calculator lets you enter the number of sides and the length of the sides and it calculates the radius.  

1. Choose the center location for the round pen, and use this calculator to compute the radius.
2. Drive a stake in the ground and use a rope that is the length of the radius to pull the corners in or out to get the maximum area of the round pen.

Panels and Post and Rail Lengths

The following are common lengths of sides (s) of a round pen:

• Rails in a Post and Rail Fence typically come:
  • 8 feet
  • 11 feet
• Metal panels for a horse pen
  • 6 feet
  • 8 feet
  • 10 feet
  • 12 feet
  • 16 feet