There is no one answer to this question as it depends on the type of knife you are referring to. For example, a chef's knife typically has a 20 degree angle, while a pocket knife usually has a 15 degree angle. The reason for this difference is that a chef's knife is designed for chopping and slicing, while a pocket knife is meant for more delicate tasks like carving and precision work. Ultimately, it comes down to personal preference and what you will be using the knife for most often.