Hi
I bought 1/2 yard of two coordinating fabrics to make mine. I did download a pattern for the half circle online....but can't put my finger on the site right now, I had done a search. I will get four napkins, about 16 inches each from it.
It's basically a half circle of two fabrics sewn together, turned, folded, and pressed. The bigger your half circle the bigger the napkin, have seen them with a full circle also, but that looked bulkier to me.
Hope that helps you.
Bev