It is 15.5 inches square. I roll out my cookie dough inbetween parchment paper and then chill, and the dobord hardly gets dirty at all. Just a little wipe down afterwards and that is it. It is very easy to use, just adjust it to the thickness you want (I prefer 1/4") and I leave it at that adjustment all the time. I got one for my mother-in-law for an early christmas gift and she used hers for the first time yesterday. She loves it as well!