Especially if you are creating your own crock pot recipe, it can be hard to know how full it should be when you are busy creating a masterpiece. Fortunately, there is a rule of thumb you can follow to ensure that your meal will be cooked through without being overcooked.
Ideally, the slow cooker should be at least half full, yet no more than three quarters full. For the perfect slow cooker cooking environment, aim for your crock pot to be about two thirds full.
Some recipes do call for it to be less than half full, so don’t be alarmed if that is the case. This also may be due to some ingredients being added later in the cooking.