The bake time for sweet potatoes will vary a bit depending on how big they are. Smaller sweet potatoes will take about 30 to 40 minutes to bake, whereas large sweet potatoes can take up to an hour. In order to make sure your sweet potato is fully baked, you can test it by piercing it with a fork; if it slides in easily, the potato is done.
Like with regular potatoes, be sure to prick the skin of your sweet potatoes before you put them into the oven. This allows steam to escape, so your potatoes don’t explode in the oven.