30-inch

• Thirty-inch ovens are the standard for most homes and most kitchens. The inside dimensions of the oven are approximately 25 inches wide and 16 inches high. The oven will be approximately 16 inches deep. This height will accommodate at least two oven racks and can fit three.
  
  

27-inch

• In a 27-inch oven, the width changes but not the height or depth. The width is approximately 22 inches, and the depth and height both remain approximately 16 inches.
  
  

24-inch

• The 24-inch oven is useful for a smaller galley kitchen in an apartment or studio. The interior dimensions are narrower with a depth and height similar to other larger ovens. Generally, the ovens are 17 inches wide, 16 inches high and 15 inches deep.
  
  

20-inch

• Twenty-inch ovens are the smallest sized oven generally available at most home improvement or appliance stores. Because of the decreased width, the oven actually tends to be a nearly perfect square that is 16 inches deep, 16 inches wide and 16 inches high.