Step 1

Cut off the bottom hem of the T-shirt. Measure the circumference of baby’s head and divide by 2 (or get your hands on another hat that you know fits and measure it) to get x". Mark that measurement from one of the corners at a 45-degree angle from the bottom edge of the T-shirt.
Step 2

Mark 13" from the bottom up the side edge. Connect that mark with the end of the line you made in step 1.
Step 4

Pin along the open diagonal edge, right sides out. Sew a running stitch or whipstitch along the pinned edge for an external seam.
Step 5

Remove the pins and tie the tip of the hat in an overhand knot, leaving about 2" at the top. The bottom edge will curl naturally.
Step 6

This project is excerpted with permission from <a href="http://www.amazon.com/gp/product/0761154108/ref=as_li_qf_sp_asin_il_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=0761154108&linkCode=as2&tag=craftfocom-20">"Generation T: Beyond Fashion"</a> by Megan Nicolay and published by Workman Publishing.