A:Answer 12 3/8"D x 14 5/8"W x 7 5/8"H
As you can see from the picture of the drip pan, the center is actually about 13 1/2"D, but you can't fit a pan that size in the oven. It is only that deep where the pizza pan fits.
Also, if someone is trying to purchase another rack, 14 1/2" will fall through the guides on the side and 14 3/4" will be a tad too wide.
I hope this helps!