How many sts for this cowl?

I really want to this hoooded cowl. I cant find any patterns that are just like this. I would be using chunky yarn. I would knit it in a seed st probably. how many sts would i need to make this?

Very nice! Best to make a gauge swatch with your yarn and needles to see how many sts to cast on. Maybe this pattern can help with the size too.
http://www.ravelry.com/patterns/library/laras-cowl