Cooking Temperature For Baked Potatoes. In a conventional oven, bake your potato for 45 minutes at 400° or 60 minutes at 350°. These times and temperatures will vary according to the size of your potatoes. Check to see that your baked potatoes are ready by poking them with a toothpick and testing for tenderness.hen it comes to baked potatoes, the cooking times vary dramatically, depending on which method you’re using. Here are answers to frequently asked questions about cooking times for baked potatoes. How Long To Bake A Potato. Bake a potato for 45 minutes, in the oven at 400°.