Foil-wrapped baked potatoes take 20 to 40 minutes to bake. The larger the potatoes, the longer they take to cook. Cooking many potatoes together also increases cooking time.
Although baking potatoes in foil takes longer than baking them without foil, starting them in a preheated oven helps to minimize the cooking time. Global Post recommends setting the oven to 425 degrees Fahrenheit.
The potatoes should be washed well, and then pricked in several places to keep them from exploding from the steam that builds as the potatoes heat. Rubbing the potatoes with olive oil and seasonings before wrapping increases the potatoes' flavor.