16.5, don't use it as much as my 12.5 but comes in handy now and then. Got it at a yard sale for 8 dollars. One of our guild members passed away and her daughter had all her quilting supplies in a yard sale. Most of the items were over priced so when I saw 8 on this, I grabbed it quickly. I'm sure they didn't know the actual cost or it would have been much more.