Choosing Cable size

As a newb to knitting, i have graduated from hats now am trying a cowl, casting on 240 stitches, how long of a cable would you need for that many stitches?

Rule of thumb is that a cable can hold 2-3 times the number of sts versus the final width.

So, a 10 inch cable could hold enough sts for your project to be 20-30 inches wide in your gauge.

More for finer yarns. Less for thicker yarns.

that makes it easy to remember- here is the pattern. I had someone say you don’t want to put that many stitches on KP or in my case Dreamz, does that make sense??

[FONT=Calibri][SIZE=3][FONT=Calibri][SIZE=3]
FINISHED SIZES
S, (L) [Shown in Large]
Small: 49 inches in circumference
Large: 74 inches in circumference
DIRECTIONS
CO 160 (240)

See if this table helps. You’re working at about 3-4 sts per inch and more sts than listed but I would guess a 36 inch circular would work. Note that the number of sts in the table is the minimum that will work.
Would you edit the pattern in your post to delete the second half please? That way we won’t get into any copyright issues. Thanks.