Well, I measured mine and SURPRISE, I have the 12" model after all, not the 14". The "working area" of mine is 12" x 12" (up to the handle rivets).
So, I'd guess that the bigger one is 14" wide x 16" long, not counting the handle.
BUT, Amazon has the 16" wide one on sale for 51% off, which means it's only $1.80 more than the 14" one. Like I say "Go Big or Go Home!"