Making an octagon is is very easy if you start with a true square. Simply multiply your WIDTH (x) 0.41421 and that is your edge length. Here is the rest of my formula.
0.41421 = EDGE LENGTH
0.29291 = PUP LENGTH
0.54119 = OCTAGON CENTER
Square to Octagon the Easy Way DIY length x 0.4142 simple math
This is the easy method of creating an Octagon from a square. This is much easier than other octagon creation methods. SEE BELOW
EDGE LENGTH
Length (x) 0.41421 = brace length
SQUARE CORNER TO START PUP LENGTH
Length (x) 0.29291 = length, square corner to rail end
CENTER OF LONG DIAGONAL
Length (x) 0.54119 = octagon point to point center
HOW TO:
FOR INSERT BRACES:
Multiply your width (x) 0.41421 or 0.4142 = the length of your brace or edge length.
FOR CUTOUT OCTAGONS:
Start with a square, multiply your square’s length (x) 0.29291 or 0.293 measure from square’s corner out and mark at the value. Do this from all 4 corners in all directions 8 times. Line up and cut off = square to octagon.
FIND THE CENTER WITH ONE LINE:
Multiply original length (x) 0.54119 or 0.541
This is your long diagonal length at 1/2 = the center.
Online Calculator:
