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Potato Calculator
How many potatoes per person for mash, roast potatoes or potato salad — the quantity changes with what you are making.
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Potatoes
2.0 kg (4.4 lb)
Medium potatoes (about 170 g each)
12
Butter and cream, if mashing
200 g + 240 ml
Salt for the water
20 g
Two hundred and fifty grams a head for mash, a little less for roasties, and two hundred for potato salad — which people eat less of than they expect, because it sits alongside four other things.
Mash and roast want different potatoes. Floury varieties — russet, Yukon Gold, Maris Piper — fall apart when boiled, which is exactly what mash needs and exactly what ruins a potato salad. For salad use a waxy potato that holds its shape: new potatoes, fingerlings, red-skinned.
Start potatoes in cold, well-salted water and bring them up together. Dropping them into boiling water cooks the outside to mush while the centre is still hard, and no amount of mashing recovers the texture you lost in the first three minutes.
Questions people ask
How many potatoes per person?
About 250 g for mash — roughly one and a half medium potatoes — or 200 g for potato salad. Buy a little over: nobody has ever complained about extra roast potatoes.
How much potato salad for 20 people?
4 kg of potatoes, which makes about 5 kg of finished salad with the dressing and add-ins. It is a side dish sitting beside others — 200 g a head is generous, not tight.
Can I make mashed potatoes ahead?
Yes. Mash them, cover the surface directly with plastic wrap, and reheat over low heat with a splash of warm cream, stirring. Do not reheat in a microwave on high — it turns them gluey.