This is a pattern for a top-down, seamless knit hat that is then felted. It is ingeniously cast on with DPNs in a square, and knit down towards the brim. Lots of fun to make, and very easy to customize.
Note that when smoothed over a bowl during drying you will get a curved top, and that felt can be slightly stretched at that stage if needed. Also, each yarn felts somewhat differently, so if you use a yarn other than Cascade 220, you may get different size results!
My hats felt down to 20” to 21 inches around, but felting can be unpredictable depending on your chosen yarn, degree of agitation while felting and temperature of the water. Sized for adult head.