Start by measuring your height, from the bottom of your chin to your ankles. Double that number.
Now, measure your cloth width-wise from arm-to-arm outstretched.
You'll also need a 9x9 piece of extra cloth.
For me, my fabric is 65x65 (counting the 9x9 and leftover, cut it off before sewing)
I'm using the leftover fabric for the hood(not posting, sorry)
Fold the cloth in half length-wise. Then in half width-wise.
Measure your waist, cut out a rectangle in the corner AWAY from the folds, Example: 11 inches in from the side.
You can decide how wide you want the robe arms.
put a quarter-circle and the corner where both folds are, the radius should be 3 inches.
unfold, cut a 6 inch diameter hole in the middle and sew to the neck hole in the fabric (the 3-inch quarter-hole we cut)
this is the hem for the robe
fold it in half length-wise and sew the fabric along the sides NOT SEWING THE BOTTOM OR ARMS CLOSED.
VIOLA! The robe is done.
TIP: If you want to hide the seams, turn the robe inside-out when you're done and make sure you sew the square fabric on the OPPOSITE SIDE before the step's completion.
Price of the Fabric: like, $5-8
Price for a pre-sewn robe: $25-40+