A countertop oven generally offers more capabilities than a toaster oven. A toaster oven is best for small tasks like toasting or reheating, but may not be able to reach the same temperatures of a countertop oven. They are also less likely to offer advanced features like roast, proof or dehydrate.
A countertop oven comes with a wide range of capabilities and can often stand in for a full sized oven, especially when cooking a dish for one or two people. Because a toaster oven usually comes with a more streamlined set of functions, they’re less likely to have convection capabilities. However, there are several convection countertop ovens on the market that offer all the benefits of convection cooking in a compact, countertop-friendly size.