Party food calculator

The guest list first becomes adult portions: each adult is one portion and each child counts as half. Every item has an amount for one adult, which appetite scales up or down. That amount is multiplied by the portions, any extra on top is added, and the total goes up to a whole piece or the next 100 g of salad. The list therefore never falls short of the sum.

Appetite multiplies every amount by 0.75 for light eaters and by 1.25 for big eaters, so a normal portion becomes 75% or 125% of itself. Weights are raw, as bought. Meat and potatoes lose weight in the pan, so a cooked plate weighs less than the figures here.

The result leads with the meal's main item, then lists the rest, the adult portions and a table per adult, per child and to buy. The shopping list underneath copies to the clipboard, and nothing typed leaves the browser.

A three hour finger buffet for 24 adults and 6 children takes 108 sandwich quarters, 216 savouries, 850 g of crisps and 54 sweet bites. Those 30 guests make 27 adult portions, because the children count as half.

Food for a party is worked out per head, not for the party as a whole. Count the adults, add half a portion for each child under 12, and multiply each dish by that number. Teenagers aged 12 and over count as full adults. The buffet menu starts every adult on 4 sandwich quarters, 4 savouries and 2 sweet bites. Savouries rise by 2 a head for every hour after the first. Appetite can lower everything by a quarter or raise it by a quarter. Each total is then rounded up to full packs and pieces, so the shopping covers the sum. An extra percentage on top allows for unexpected guests or second helpings.

Stretch the same party to five hours and the savouries climb to 324, while the sandwiches stay at 108. Worked cases with their sums appear under checked against known answers.

Each adult gets 2 sausages, 1 burger and 120 g of chicken on the barbecue menu, with 2 bread rolls and 160 g of salads. For 8 adults and 2 children that means 1.5 kg of salads and coleslaw and 2.6 kg of weighed food in all.

The chicken follows the British Nutrition Foundation, whose portion guide sizes a chicken breast at about a whole hand, 120 g. Sausages, burgers, rolls and salads are starting figures of the tool's own: a roll for the burger, one for a sausage and two 80 g servings of salad.

With big eaters the chicken rises to 1.4 kg and the sausages to 23. With light eaters they fall to 900 g and 14. Every weight is raw weight, as it comes from the butcher's counter or the pack.

The Food Standards Agency's barbecue advice says chicken, pork, burgers, sausages and kebabs must be cooked through: steaming hot, no pink meat, juices running clear. A charred outside does not mean a cooked inside, so it suggests starting thick pieces in the oven.

A finger buffet is counted in pieces rather than grams. Every adult starts on 4 sandwich quarters, one round cut into four, plus 4 savouries such as sausage rolls, mini quiche squares or samosas.

Nibbles add 30 g of crisps a head and 2 cakes or sweet bites. With counted and weighed food mixed, the calculator shows no single weight per adult here: the shopping list counts the pieces and weighs only the crisps.

Guests keep eating while a buffet stays out, so its length matters. From the second hour the savouries go up by 2 for each guest, while sandwiches, crisps and sweets stay as they are. Every amount on this menu is a house figure.

Ten adults at Christmas dinner need a 5 kg turkey, 2.5 kg of potatoes, 2.4 kg of vegetables and 30 pigs in blankets. The turkey is the whole bird, bones included, at 500 g a head, rounded up to the next 500 g.

That figure comes from BBC Good Food's Christmas portion planner, a magazine's guide. It says a medium turkey of 4 to 5 kg feeds 8 to 10, and a turkey crown of 2 to 2.5 kg feeds 6.

The planner counts 140 to 175 g of cooked turkey per person and 240 g of vegetables, three 80 g portions. It adds that big eaters can take the higher of its two amounts. The 250 g of roast potatoes and 3 pigs in blankets a head are not from the planner.

Recipes that give the oven in gas marks or for a fan oven convert with the oven temperature converter.

Each child under 12 counts as 50% of an adult portion. The rule comes from the Verbraucherzentrale NRW, a German consumer advice centre. Its party brochure counts children from about 6 as half a portion and from 10 to 12 as full eaters.

Younger children eat less than half, so counting every child under 12 as half leaves a small cushion at a children's party. Teenagers count as adults. For 15 children and 6 adults over two hours, the buffet comes to 13.5 portions and 54 sandwich quarters.

The same brochure plans about 800 g of food per guest at a buffet, around 1,000 g for good appetites and 600 g for small ones. Those ratios give the appetite factors: light eaters at 75% and big eaters at 125% of a normal portion. No British source gives both a child share and appetite factors.

Of the 13 starting amounts, 3 come from a listed source: the chicken, turkey and vegetables. The other 10 are the calculator's own choices, made because no UK body publishes such figures.

Switching the amounts to "My own" opens a field for every item of the chosen meal, each a normal amount for one adult. Light or big eaters, the hours and the extra on top still count. Allowing 4 pigs in blankets each instead of 3 makes 40 for ten adults.

A price for the meal's main item turns the list into a budget: per sausage for a barbecue, per sandwich quarter for a buffet, per kilogram of turkey. At £8.00 a kg, a 5.5 kg bird for 10 adults and 2 children costs £44.00. That is £3.67 per guest, with children counted as whole guests.

For a sense of prices, the Office for National Statistics (ONS) put average pork sausages at £6.78 a kg and chicken fillets at £9.10 a kg in August 2026. A 454 g pack of beef burgers averaged £4.06 and a six pack of rolls £1.26. Shop prices differ from these averages.

The Food Standards Agency's community cooking guidance says sandwiches should never sit out for more than 4 hours. After that they go back in the fridge or in the bin, so a long buffet is often served in rounds.

Its barbecue advice keeps chilled food in the fridge or a cool bag until it is needed. Leftovers go in the fridge within 1 to 2 hours, are eaten within 48 hours and are reheated only once.

For cooking in general, the agency's test is the centre of the food reaching 70 °C for 2 minutes.

The UK wasted 10.2 million tonnes of food, according to WRAP's key facts published in July 2025. Households accounted for 6 million tonnes, or 58%, and 4.4 million tonnes of that could have been eaten.

Rounding up adds at most one buying step per item, and an extra on top adds a share the host chooses. A total per head shows where any surplus lies before the shopping is done, and leftovers chilled in time can become the next day's lunch.