How many bottles of drink do you need for a party?

Choose a number of glasses per guest per hour yourself and multiply that by the number of guests and the number of hours your event lasts.

If you count on one and a half glasses per hour, a party of 40 guests lasting 5 hours comes to 300 glasses. If you count on one glass per hour, it is 200. In practice the first hour runs higher than the last, so count that hour double if you want to be on the safe side.

Then round up to whole packs. Unopened crates and bottles can be kept, so that margin costs you nothing.

Pils accounts for almost 75 percent of beer sales in the Netherlands, so fill most of your beer with pils.

A split of three parts pilsner to one part specialty beer follows that ratio and still keeps the choice broad. Offer specialty beer by the bottle instead of by the crate, and you won’t be left with half a crate of one kind.

Craft beer usually comes in bottles of 33 centilitres, while lager is more often found in crates of 24 bottles of 30 centilitres. Convert those two sizes separately, otherwise your number of glasses will not be right.

A keg of 20 litres yields 80 glasses of 25 centilitres, a keg of 30 litres 120 glasses and a keg of 50 litres 200 glasses.

If you tap smaller glasses of 20 centilitres, that yields 100, 150 and 250 glasses. A crate of 24 bottles of 30 centilitres is 7.2 litres, a crate of 24 bottles of 33 centilitres almost 8 litres.

The Voedingscentrum counts 250 millilitres of 5 percent beer as a standard drink. A 30 centilitre bottle therefore counts for slightly more than one drink.

In the Netherlands, 1 in 12 beers drunk is alcohol-free, so reserve at least that share of your beer for alcohol-free bottles.

Tel daar de gasten bij op die rijden of geen alcohol drinken, en de gasten onder de 18. Voor hen geldt NIX18: geen alcohol, ook niet thuis. Komt u op tien alcoholvrije gasten van vijf uur, dan staan daar bij anderhalf glas per uur 75 glazen tegenover.

Besides the alcohol-free bottles, allow a glass of water or soft drink per guest per hour. That goes faster than people expect, especially in warm weather.

From a 75 centilitre bottle of wine you get seven glasses of 100 millilitres, from a 70 centilitre bottle of spirits twenty glasses of 35 millilitres.

Those measures come from the Voedingscentrum, which counts 100 millilitres of 12 percent wine and 35 millilitres of 35 percent spirits each as one standard drink. If you pour more generously, divide by your own measure: with 150 millilitre glasses you get five glasses from a bottle of wine.

Divide your guests by what they drink and calculate each group separately. A bottle of spirits serves fourteen mixed drinks at 5 centilitres per glass.