Portions per person
How much pasta for 6 people? Pick the food and how many you are: the total is calculated instantly (children count as half a portion).
Recommended portions per person
Where these portions come from
They are the «cookbook» portions used in Italian cooking, in line with standard nutritional guideline servings (e.g. 80 g of pasta). The per-person amount is editable: if your guests are hearty eaters, raise it.
The children trick
In the count a child is worth half an adult portion: for a dinner with 4 adults and 2 children, calculate 5 portions. For hungry teenagers, count full portions!
The portions people actually use
These are the ones behind this page, and they're worth knowing by heart because they come up every time you shop: 80-100 g of dry pasta or rice a head when it's the only course, 60-70 if it's one of many dishes; 150-200 g of meat or fish for a main; 200 g of vegetables as a side; 50-60 g of bread. For home-made pizza, 250 g of dough per person for a round one.
The two factors that shift everything
The first is children: up to about ten they count as roughly half a portion, and that isn't a rule of etiquette, it's that they really do eat half. The second is how many dishes there are: the same person at a four-course menu eats far less of the first course than they would if that course were the whole meal.
At a standing buffet, on the other hand, people eat more than you'd predict, because they taste everything without noticing: the practical rule is 12-15 «bites» a head if the buffet replaces dinner, half that if it's drinks before going on somewhere.
Better to over-cater, but not on everything
It's worth over-catering on what keeps or gets reused: bread, vegetables, sauces, breakfast cakes. It isn't worth it on what has to be thrown out the next day, like dressed salads, cut fruit and anything fried. The most honest calculation is for one person more than the real number, which covers unexpected appetite without filling the fridge with sad leftovers.
Nearby tools
To rework a recipe written for a different number of people there is Scale a recipe, and for a different tin size Cake servings. To measure without scales Kitchen measures, and to split the shopping bill among those who were there Group expenses.