Every one of these five listings publishes a Capacity field, and on all five it is either wrong or unusable. Breville says 0.8 cubic feet while publishing an interior of 13.5 by 11.5 by 5.5 inches, which is 0.49. Ninja says 19.7 cubic inches, for an oven its own gallery panel calls 8 quarts, about 462 cubic inches. Panasonic says 0.04 cubic feet, which is 69 cubic inches, for an oven that takes four slices of bread. BLACK+DECKER says 8 liters, about 0.28 cubic feet, on a listing whose bullet 1 says it takes a 9 by 13 inch pan and whose product description adds a 12 inch pizza. Cuisinart says 0.6 cubic feet and publishes no interior dimension at all, so there is nothing to check it against.
Two numbers survive. The first is the full interior in inches, and only Breville prints all three. Ninja prints one of them, an interior height of about 3 inches. The second is the footprint, which is the depth times the width from the Item Dimensions field on every one of the five listings. That gives 156 square inches for the Panasonic at 12 by 13, 193 for the Cuisinart at 12.25 by 15.75, 264 for the Breville at 13.9 by 19, 295 for the Ninja at 19.72 by 14.96, and 319 for the BLACK+DECKER at 14.5 by 22. Those are our multiplications of the two numbers in each listing's Item Dimensions field, not figures anyone publishes. Measure your counter, then work backwards.