The cooking time for boiling potatoes for mashed potatoes can vary depending on the size and type of potato, as well as your preferred texture. As a general guideline, it typically takes 20-25 minutes to boil medium-sized potatoes until they are soft enough to mash easily.

To boil potatoes for mashed potatoes, follow these steps:

  1. Peel and chop the potatoes into evenly sized pieces.

  2. Place the potatoes in a pot and cover them with cold water. Add a pinch of salt to the water.

  3. Bring the water to a boil over medium-high heat, then reduce the heat to medium-low to maintain a gentle simmer.

  4. Cook the potatoes until they are tender when pierced with a fork or knife, about 20-25 minutes.

  5. Drain the potatoes in a colander, then return them to the pot.

  6. Mash the potatoes with a potato masher or electric mixer, adding butter, milk, salt, and pepper to taste.

Remember to taste the potatoes as you go, and adjust the seasoning and consistency as needed to get your desired result.