For a four-hour party, plan on about three mixed drinks per spirit drinker, which means three 150ml mixers each, plus around 1kg of ice per guest. Drinks House 247 suggests a 1:3 ratio of spirit to mixer for a highball, so a 50ml measure needs about 150ml of tonic, soda or ginger ale.
Running out of tonic halfway through a party is more common than running out of gin. Mixers are cheap, bulky and easy to forget, and they go flat once opened, so it pays to work the numbers out before you shop. The calculation is simple once you know how many people will drink spirits and how long the party runs.
A widely used planning rule is two drinks per guest in the first hour and one drink per hour after that. For a four-hour party, that is about five drinks per person in total. Not everyone will drink spirits: at a typical mixed party, around a third to a half of guests choose spirit-and-mixer drinks, with the rest on wine, beer or soft drinks.
So for each spirit drinker at a four-hour party, plan on three to four mixed drinks, and round up rather than down.
| Drink | Spirit | Mixer | Ratio |
|---|---|---|---|
| Gin and tonic | 50ml gin | 150ml tonic | 1:3 |
| Vodka soda | 50ml vodka | 150ml soda water | 1:3 |
| Rum and ginger | 50ml rum | 150ml ginger beer or ale | 1:3 |
| Whisky highball | 50ml whisky | 150 to 200ml soda water | 1:3 to 1:4 |
| Paloma | 50ml tequila | 150ml grapefruit soda, plus lime | 1:3 |
A 50ml pour is a UK double. If your guests prefer singles (25ml), the same mixer quantity applies; the drinks are simply lighter. A 70cl bottle of spirits gives 14 doubles or 28 singles.
| Spirit drinkers | Mixed drinks (4 hours) | Mixers needed (150ml each) | 70cl spirit bottles (doubles) |
|---|---|---|---|
| 10 | 30 to 40 | 6 litres | 3 |
| 20 | 60 to 80 | 12 litres | 5 to 6 |
| 40 | 120 to 160 | 24 litres | 9 to 12 |
| 60 | 180 to 240 | 36 litres | 13 to 18 |
The mixer column is based on the upper figure plus a margin. Ice is separate: plan about 1kg per guest at the whole party, not just per spirit drinker, because everyone's drinks need it.
Small bottles and cans, usually 150ml to 200ml, are almost always the better buy for a party. Each one is opened for one or two drinks, so nothing goes flat on the table. A one-litre bottle loses its fizz within an hour of opening at room temperature, and half-finished bottles end up poured away. Large bottles only make sense if a bartender is pouring steadily from a cold well.
Split your order by the spirits you are serving. A sensible starting split for a mixed party:
Add plenty of still and sparkling water on top. Offering water alongside alcohol is good hosting and helps guests pace themselves.
Chill mixers for at least a few hours before the party, and keep only what you need in the fridge or ice bucket, topping up from a reserve. Cold mixers stay fizzy longer and dilute drinks less. If supplies run low mid-party in London, a top-up delivery typically arrives within 30 to 45 minutes.
Plan on about three 150ml mixers per spirit drinker for a four-hour party, and round up. Small bottles or cans waste less than large bottles.
A ratio of about 1:3 works well: 50ml of gin to 150ml of tonic. Use more tonic for a lighter drink.
Allow around 1kg of ice per guest, and more in hot weather or if you are chilling bottles in buckets as well as serving drinks.
A 70cl bottle gives 14 doubles of 50ml or 28 singles of 25ml.
Browse mixers, gin, vodka and beers, or see how alcohol delivery works across London. For planning the rest of the party, use our party alcohol calculator, read how much ice you need and how many drinks a bottle of spirits makes.
Deliveries are to over-18s only under our Challenge 25 policy. Please drink responsibly.
