For 20 people, you will need approximately 10 to 15 pounds of potatoes, depending on the other dishes being served and the appetite of your guests. As a general guide, you can plan on serving about 1/2 to 3/4 pound of potatoes per person, depending on the other dishes being served and the appetite of your guests. For 20 people, you will need approximately 10 to 15 pounds of potatoes.
If you are serving a large meal with several other dishes, you may want to plan on the lower end of this range (1/2 pound per person). If potatoes are the main dish or you are serving a smaller meal with fewer other dishes, you may want to plan on the higher end of this range (3/4 pound per person).
It’s always a good idea to have a little extra on hand, just in case, so you may want to consider purchasing a few extra pounds of potatoes to be safe.