Potato Calculator — How Many Potatoes Per Person

Background.

The reason "how many potatoes per person?" has no single answer is that potatoes shrink by wildly different amounts depending on what you do to them. USDA's Food Buying Guide, the yield table school kitchens use to buy food for millions of meals a day, publishes a separate figure for each preparation of white or russet potatoes, and the spread is nearly two to one: a pound as purchased gives 2.48 cups of peeled cooked slices, 2.23 cups of peeled diced, 2.10 cups of mashed, but only 1.69 cups of baked potato and 1.33 cups of hash browns. Shredding and frying drives off the most water; slicing and boiling drives off the least. Use one number for all of them and you will over-buy for a gratin and badly under-buy for a hash brown breakfast.

This calculator takes the preparation, the number of people and how much finished potato each person gets, and returns the raw as-purchased weight to buy, the number of individual potatoes that is at your chosen size, and — for peeled preparations — how much of that weight the peelings will take away. Peeling is not a rounding error: USDA puts ready-to-cook pared potato at 0.81 lb per pound purchased, so almost a fifth of what you carry home goes in the bin, and the yields above already have that loss baked into them.

The serving size is yours to set, and it is the input that most changes the answer. Half a cup is USDA's school-meal vegetable serving, which is modest. A cup is a generous holiday portion — and it is worth noticing that a cup of mashed potato per person works out to 0.48 lb of raw potato, which is the familiar "about half a pound each" rule of thumb that recipe writers have been repeating for decades. The rule turns out to be right, for that portion size and that preparation only.

The main thing this page does not do is tell you how much butter, milk or cream to put in the mash. That is deliberate. No primary source publishes a butter-to-potato ratio, because it is a recipe decision rather than a yield, and every mashed potato recipe worth following states its own. What every one of them scales from is the weight of potatoes — which is exactly what this page gives you, so pick your recipe and multiply.

Two scope notes. All figures are for white or russet potatoes; sweet potatoes, red potatoes and new potatoes have their own USDA rows with different yields and are not covered here. And the potato count assumes uniform potatoes at the size you select, which no real sack contains — weigh if it matters, count if it does not.

What is potato calculator?

A potato calculator converts a number of servings into the weight of raw potatoes to buy, using a published yield for the specific way the potatoes will be cooked. It exists because potato yields are preparation-dependent to a degree that surprises most cooks: hash browns need nearly twice as much raw potato per finished cup as scalloped potatoes do.

This page runs on USDA's Food Buying Guide for Child Nutrition Programs, Section 2 (Vegetables), rows for fresh white or russet potatoes. For each preparation the guide states how many ¼-cup servings of finished potato one pound as purchased yields; multiplying by 0.25 gives cups per pound, which is the conversion factor this calculator applies. It also uses USDA's published trim figure — 1 lb as purchased = 0.81 lb of ready-to-cook pared potato — to show how much of the purchase weight the peelings account for, and USDA's own count sizes (120 count ≈ 6 oz, 100 count ≈ 8 oz, 80 count ≈ 10 oz) to turn pounds into a number of potatoes.

How to use this calculator.

1. 01Choose the preparation. The published yield for each is shown in the dropdown, because that number is doing all the work.
2. 02Enter how many people you are feeding.
3. 03Set the cups of finished potato per person — ½ cup for a normal side, 1 cup for a generous holiday portion.
4. 04Pick the size of potato you will buy; this changes the count, not the weight.
5. 05Read the raw as-purchased pounds at the top. That is what to weigh out at the shop.
6. 06Check the peel-waste figure if you are peeling: about a fifth of the purchase weight for pared preparations.
7. 07For mashed potatoes, take the potato weight to your recipe and scale its butter and dairy from there — this page does not guess at those.

The formula.

USDA's table is stated in ¼-cup servings per pound as purchased, so the first step is to turn that into cups per pound: mashed potatoes are published at 8.40 servings per pound, and 8.40 × 0.25 = 2.10 cups per pound. Ten people at one cup each need 10 cups of finished mash, so the purchase weight is 10 ÷ 2.10 = 4.76 lb. At 8 oz per potato — USDA's 100-count size — that is 4.76 ÷ 0.5 = 9.52 potatoes, rounded up to 10, because you cannot buy half a potato and running short is worse than having one left over.

Peeling loss is applied separately, from USDA's own trim cell: 1 lb as purchased = 0.81 lb of ready-to-cook pared potato. Of the 4.76 lb bought, 3.86 lb reaches the pot and 0.90 lb is peelings — 19%. That loss is already inside the 2.10 cups-per-pound yield, so it is reported for information rather than added on top; adding it twice is the single easiest way to get this calculation wrong.

The per-person figure falls out of the same arithmetic and is worth keeping in your head: 4.76 lb ÷ 10 people = 0.48 lb each. The old cook's rule of half a pound of potatoes per person turns out to be exactly a one-cup mashed serving, which is a satisfying case of folk knowledge and a federal yield table agreeing.

The yields differ enough between preparations to change a shopping list. For the same 10 cups of finished potato: sliced and peeled at 2.475 cups per pound needs 4.04 lb; diced with the skin on at 2.425 needs 4.12 lb; mashed at 2.10 needs 4.76 lb; baked whole with the skin at 1.69 needs 5.92 lb; and hash browns at 1.325 need 7.55 lb — nearly twice the sliced figure. The physical reason is water and surface area: shredded potato fried in a pan loses a great deal of moisture, while sliced potato baked in cream loses very little.

One source note about the baked row. USDA publishes baked-potato cup yields only for its count sizes, not for the 'all sizes' row every other preparation here comes from, so the 1.69 cups per pound figure is the 100-count (about 8 oz) row. The neighbouring rows are 1.63 for 6 oz potatoes and 1.75 for 10 oz, so the choice moves the answer by about 4% either way. Everything else on this page is from the 'all sizes' row and carries no such caveat.

Nothing is rounded until the end, with one deliberate exception: the potato count is rounded up, which is a real-world decision rather than a rounding error, and the pound figure it derives from is left unrounded.

A worked example.

Frequently asked questions.

References& sources.

1. [1]U.S. Department of Agriculture, Food and Nutrition Service. "Food Buying Guide for Child Nutrition Programs," Section 2 (Vegetables) yield table, heading "Starchy Vegetables — POTATOES", rows "Potatoes, fresh / White or Russet, All sizes, Whole" (8.40 servings of ¼ cup pared cooked mashed per lb; 8.90 diced; 9.90 sliced; 5.30 hash browns; 9.70 diced with skin; "1 lb AP = 0.81 lb ready-to-cook pared potatoes") and the 120/100/80 count rows (approx. 6, 8 and 10 oz each; 6.53/6.76/7.01 servings of ¼ cup baked with skin per lb). Retrieved 2026-07-30; the yield-table PDF carries no printed revision date.
2. [2]U.S. Department of Agriculture, Food and Nutrition Service. Food Buying Guide interactive tool and yield-table index ("Welcome to the Food Buying Guide") — the source that hosts the Section 2 yield table and its column structure: food as purchased (AP), purchase unit, servings per purchase unit for the edible portion (EP), serving size, and additional information. Retrieved 2026-07-30; the tool states no edition or revision date.
3. [3]U.S. Department of Agriculture, Agricultural Research Service. "Nutritive Value of Foods," Home and Garden Bulletin No. 72 (2002 revision) — items 1163–1165: a baked potato with skin weighs 202 g and is 71% water; its flesh alone is 156 g at 75% water; the skin alone is 58 g at 47% water. This is the moisture picture behind the yield differences between preparations.