Nobody runs out of food
Ask anybody who has hosted something what went wrong and it is never the sausage rolls. There is always food left. What runs out is the same five things every time, and none of them are on the shopping list because none of them feel like the party.
Ice
Half a kilo a head normally and a full kilo in warm weather, which for forty people is forty kilos. Your freezer holds a bag. And it is the one item here that cannot be bought the day before: no shop has thirty kilos on the shelf on a hot Saturday afternoon. Order it, buy it through the week, or borrow freezer space.
Glasses
Two to three each, not one. People put a glass down, lose track of it and take a clean one, and by the end of an evening forty people have used about a hundred. Hiring is usually cheaper than buying at that number, and the good part is that they take them back dirty.
Soft drinks
The most reliably under-bought thing at any party, and the cause is always the same: the host counts the drivers and buys for them. But everybody drinks soft drinks through an evening, and somebody not drinking alcohol gets through more of them, not fewer.
So the figure here is calculated for the whole room and does not move when you change the mix of drinkers. That is deliberate.
Bin bags and loo roll
Trivial, and the two things you genuinely cannot improvise at eleven at night with thirty people in the house.
Drinks are per person per hour
"Two bottles of wine each" means nothing without knowing whether it is a two hour drinks or an all-day thing. The planning figure that works is:
Two drinks in the first hour, then one an hour after that.
People arrive thirsty and then settle. Which means a two hour party is three drinks a head and a four hour party is five, so doubling the length does not double the drink. Getting that the wrong way round is how people end up with four crates left over and no ice.
These are planning figures, not a promise
Every group is different. A room full of twenty year olds and a room full of grandparents want different amounts of different things, and a work do behaves differently from a birthday.
So treat all of it as a starting point that is roughly right rather than a shopping list that is exactly right. The value is in the shape of it: knowing that the ice and the glasses matter more than one more tray of sandwiches, and knowing which of the two you cannot fix on the day.
Everything is worked out on your own machine. Nothing is uploaded and there is no account.
Common questions
How much drink do I need for a party?
Reckon on two drinks in the first hour and one an hour after that. People arrive thirsty and then settle, so a two hour drinks is not half of a four hour one: it is three drinks a head against five. Multiply by the number of people, not the number of drinkers, for the soft drinks.
Why does it want soft drinks for everybody?
Because that is the shortage that actually happens. The host counts the drivers and buys for them, but everybody drinks soft drinks through an evening, and somebody not drinking alcohol gets through more of them than somebody who is. It is consistently the first thing to run out.
How much ice?
Half a kilo a head, and a full kilo in warm weather. It is also the one thing on the list you cannot buy the day before: a freezer holds a fraction of what a party gets through and a shop will not have thirty kilos on the shelf on a hot Saturday.
How many glasses?
Two to three each, not one. People put a glass down, lose it and take another, so forty people get through about a hundred glasses over an evening. Hiring is usually cheaper than buying at that number and they take them back dirty.
Are these figures reliable?
They are planning figures, which is not the same as a promise. A room of twenty year olds and a room of grandparents want quite different amounts of quite different things. Use them as a starting point and adjust for who is actually coming.
How do children change it?
They count for food at about 60% of an adult portion and they count fully for soft drinks, glasses and the rest. They do not add anything to the alcohol.
What about a long party?
Past about six hours, one round of food does not do it. Something at the start and something else later works far better than doubling the first lot, which just sits out and goes cold.
What is always forgotten?
Ice, glasses, soft drinks, bin bags and loo roll. Nobody runs out of sausage rolls. The tool puts those five in their own group rather than at the bottom of a list, because that is where the failure actually is.