Question: are built in ovens standard size?
Answer: Wall ovens come in standard widths of 24, 27 and 30 inches, but models can vary by as much as an inch or two, making it wise to stick with the same brand. Single Versus Double. Because a wall oven is smaller than a range oven—roughly 3.5 cubic feet as opposed to 5—having an extra oven can overcome that limitation.