Potato Calculator - How Many Potatoes Per Person?
Enter the number of guests, your potato dish, and desired serving size to find out how many potatoes to buy and prepare. Flip to Servings mode to check how many people your potatoes on hand will feed. Switch between metric and imperial units, and your results update instantly.
How to use this calculator
Choose your mode at the top. In "How many to buy" mode, enter the number of adults and children, pick the dish and serving size, and optionally add a buffer for buffets or leftovers. The calculator gives you the total raw weight and the number of potatoes to purchase. In "How many people it feeds" mode, enter the weight of potatoes you already have, and the tool tells you how many adult servings you can make from them. A detailed per-guest breakdown table is shown below the results. Switch between metric and imperial at any time.
How portion sizes work
The portions shown in this calculator are raw, unpeeled weights. Cooking always reduces weight: boiled and mashed potatoes lose roughly 25-30% of their raw weight after peeling and cooking, while baked potatoes shrink by about 20%. The raw weight figures already account for typical peel and cooking loss so you arrive at the right amount after preparation. For a standard adult serving of mashed potatoes, 175 g raw is a good starting point. Light servings (120 g) suit a small side dish, while a hearty 250 g portion is appropriate when potatoes are the star of the plate.
Choosing the right potato size
Potatoes sold loose or in bags vary considerably by size. Small potatoes weigh around 140 g (5 oz) each, medium ones around 213 g (7.5 oz), and large ones around 284 g (10 oz). For baked potatoes, you typically want large ones for the best presentation. Mashed and roasted dishes are not size-sensitive, so medium is a practical default. The potato count the calculator gives is a ceiling number: it rounds up to ensure you never run short.
Buffet and leftover allowances
For plated dinners where everyone gets one serving, no extra is needed. For buffet-style meals where guests can return for more, adding 10% is a good rule of thumb. If you actively want leftovers for the next day, 15% extra is sensible. Leftover mashed potatoes reheat well in a pan with a little butter and milk, while roasted potatoes can be crisped up again in a hot oven.
Raw potato portions by dish and serving size
| Dish | Light (g) | Standard (g) | Hearty (g) |
|---|---|---|---|
| Mashed potatoes | 120 | 175 | 250 |
| Roasted / boiled | 150 | 200 | 280 |
| Baked (whole) | 175 | 250 | 350 |
| Potato salad | 100 | 150 | 200 |
Approximate raw weight per adult. Raw weight accounts for peel and cooking loss.
Frequently asked questions
How many potatoes do I need per person?
For a standard adult portion, plan on 175 g (about 6 oz) of raw potato for mashed, 200 g for roasted or boiled, 250 g for a whole baked potato, and 150 g for potato salad. These figures account for peel and cooking loss. Children typically eat half of an adult portion.
How much mashed potato does one medium potato make?
A medium potato weighs about 213 g raw. After peeling and cooking you lose around 25-30%, leaving roughly 150-160 g of mashed potato, which is slightly less than a standard adult portion of 175 g raw. So plan on one medium potato per person for mashed potatoes as a side dish.
Should I count children as full portions?
Children under 12 typically eat about half an adult portion. This calculator counts children as 0.5 adult portions, so four children add the equivalent of two adult servings. Teenagers usually eat a full adult portion or more, so count them as adults.
How much do potatoes lose when cooked?
Boiled and mashed potatoes lose about 25-30% of their raw weight after peeling and cooking. Whole baked potatoes lose around 20% due to moisture evaporation. Fried or roasted potatoes lose the most water, sometimes up to 35%. This calculator uses raw weight including peel, so the estimates already account for typical preparation loss.
What is the best potato for mashed potatoes?
Floury or starchy varieties such as Russet (US) or Maris Piper (UK) make the fluffiest mash because they break down easily and absorb butter and cream well. Waxy varieties like Charlotte or new potatoes hold their shape better and are better suited to boiled or salad preparations where you want intact pieces.
How do I convert potato weight to cups?
One cup of mashed potatoes is approximately 240 ml and weighs about 210-240 g. If a recipe calls for 2 cups of mashed potato, you need roughly 450-500 g of raw potato. This calculator works in weight to avoid ambiguity, since the density of mashed potato varies with preparation technique.