Potatoes Per Person Calculator
Tell us how many people are eating and we will tell you how many potatoes to buy.
Answer
1 kg of potatoes
The detail
Reference and detail
Allow 250g of raw potato per adult
That is a generous couple of medium potatoes, and it holds for roast, mash or boiled. Children take about 60% of that. If potatoes are the main event rather than one of four sides, choose a generous appetite and buy a little more than the number says: cold roast potatoes are never wasted.
Peeling loses a fifth
Peeling takes off roughly 20% of the weight, so if a recipe asks for 1kg of prepared potatoes, buy 1.2kg. Waste is higher with older potatoes and anything knobbly.
Which potato for which job
Floury varieties (Maris Piper, King Edward, Rooster) roast and mash best. Waxy ones such as Charlotte hold their shape for boiling, salads and gratins. New potatoes are best simply boiled with butter and mint; they will never make a fluffy roastie.
Questions and answers
Questions about potato portion sizes
Do roast potatoes and mashed potatoes need different weights per person?
Yes. Mash uses peeled, trimmed potato that becomes denser once mashed, while roast potatoes lose some volume and moisture in the oven, so the raw weight you buy differs between the two even for the same number of people. Choose the right method on the calculator above.
How many roast potatoes is that in pieces rather than grams?
It depends on how large you cut them, since weight is a more reliable measure than a piece count. As a rough guide, halved or quartered medium potatoes give a few hearty pieces per 100g, but weigh rather than count for consistent results.
Should I peel potatoes before or after weighing for a portion?
Weigh potatoes before peeling if your recipe or the calculator's figure is for unprepared weight. Check the note on the calculator, since peeling and trimming losses can be significant, especially with knobbly potatoes.
Do new potatoes need the same weight per person as roasting potatoes?
Roughly, yes, since new potatoes are usually served boiled with skins on rather than peeled, which offsets their smaller size. Use the same per-person figure unless you're removing a lot of skin or trim.