Whether you are feeding a few family members or making mashed potatoes for a multitude, running out of this comfort food is not an option. Cook enough spuds for everyone by taking into consideration potato size and the foods the side dish will be served with.
An Average Potato Makes 1/2 Cup
A serving of mashed potatoes ranges from about 1/2 cup to about one cup. An "average" russet potato weighs a little over 5 ounces which, when cooked, is just over 1/2 cup. Potato101.com notes that 25 pounds of potatoes make about 100 1/2-cup servings of mashed potatoes, so one pound of potatoes -- about three average-sized spuds -- makes about four servings.
Pick Big and Small Potatoes
Unless you pay premium prices for "sized and graded" potatoes, a 10-pound bag likely has a mixture of small, average and large potatoes. If you don't have a scale, you can guess the number of potatoes you need by choosing the ones that are similar in size to a computer mouse. If you don't have enough average-sized potatoes, pair one that is markedly bigger with one that is considerably smaller together in a 1-to-1 ratio to get the equivalent of two average-sized potatoes.
Buffets and Big Appetites
At times, you may want to prepare more or less than a typical serving size of mashed potatoes. For instance, if you are serving a "meat-and-potatoes" dinner where mashed potatoes are the main side dish, or you have guests that may want seconds, prepare enough for each person to have closer to a cup-size serving. If you are serving 100 people potluck style, you may want to prepare less since most people won't take a full 1/2-cup serving when there are other side dishes to choose from.
Ingredients Add Flavor and Bulk
In addition to potatoes, you'll need to add other ingredients to create a memorable mash. Most recipes call for at least milk or cream, butter, and salt and pepper. The milk and butter add bulk to your potatoes and create a creamy consistency. If you add sour cream or cheese, you'll likely need fewer potatoes since these ingredients add bulk.