How long does it take to bake potatoes in the oven?

This will depend on the size of the potatoes and the heat of the oven.

If you want to bake potatoes in their jackets a useful technique is to push a metal knife (It must be completely metal like a stainless steel dining knife with no bone or plastic handles) or metal skewer right through or at least into the middle of each potato - the metal will conduct the heat into the centre of the potato and this will reduce the cooking time.

If the potatoes are large you may want to halve or quarter them and place them on a baking tray. Peeling the potatoes and cutting them into smaller portions will also reduce baking time. If you pack them close together they will take longer to cook, so space them out.

Generally about 30 - 40 minutes in a moderate oven should be enough to bake a medium sized potato. Unless you have a small oven, or are baking something else in the oven at the same time, it is not a cost effective way of cooking potatoes.