The cooktop is 36" and the oven is 30" (standard oven width). You should be able to use a cooktop over a wall oven, but it really depends on the product dimensions and how it is installed. The best course of action is to get the product sheets for the cooktop and wall oven (usually available from the manufacturer's website). Measure the available space you have from the bottom of the cabinet (where the wall oven will sit) to the top of the countertop. If this is more than the combined height of the of cooktop and wall oven than you should be ok (if the installation requires a clearance between the bottom of the cooktop and top of the oven add this distance, but in any case it's a good idea to leave some space between the two). Make sure that you can return the cooktop / wall oven in case something is overlooked or you need to make a change. Hope this helps! :)

You were a great help,,,thank you!