How many gallons of water to cover 16 square feet 1 inch deep?

Here is my take: 1 gallon of water equals 231 cubic inches 1 square foot, 1 inch tall equals 144 cubic inches (12"x12"X1") 1 square foot needs 0.624 gallons to equal 1 inch of cover (144 cubic inched divided by 231 cubic inches) 16 square feet would require 9.975 gallons of water to be covered 1 inch deep. (16*0.624) Runsky