There are 11 cups of batter in an 11x15 pan for a 2 inch layer. I would guess for an 11x13, maybe 10 cups?
11' x 13' = 20,592 square inches.
If those are inches, the area is 143 square inches.
If the given dimensions are in feet then 11*13 = 143 square feet
If you are talking about 11 by 13 inches the answer is 11x13=141.
143. To arrive at square footage, you multiply the length in feet by the width in feet.
9X12 or 11X13 takes one box of cake mix for each layer.
11ft x 13 ft = 143 square feet
1 box for a rather thin cake, but if you want a thick cake you will need 2 boxes.