Party Drink Calculator

Every caterer uses the same rule: two drinks in the first hour, one an hour after that. It reflects how people actually drink — a first round on arrival, a second while settling in, then a steadier pace once conversation takes over.

From there it is a matter of dividing the total between the things you are serving and converting into containers. A 750 ml bottle of wine pours five standard glasses. A 750 ml bottle of spirits holds sixteen 1.5 oz shots. A case of beer is twenty-four.

Two adjustments matter more than the rest. Not everyone drinks — twenty percent non-drinkers is realistic for a mixed gathering, and ignoring that overstates the whole list by a fifth. And the crowd matters: a long evening with people staying over runs about a third higher than a Sunday afternoon where everyone is driving.

1. Step 1 How many people are actually drinking drinkers = guests × (1 − non_drinker%)
2. Step 2 Drinks per person per_guest = 2 + (hours − 1) Two in the first hour, one per hour after.
3. Step 3 Total drinks total = drinkers × per_guest × crowd_factor Light 0.75, average 1.0, heavy 1.35.
4. Step 4 Split by your mix beers, wine glasses and cocktails in the proportions you set
5. Step 5 Convert to containers wine_bottles = glasses ÷ 5 liquor_bottles = cocktails ÷ 16 beer_cases = beers ÷ 24 mixers = cocktails ÷ 3 litres
6. Step 6 Ice ice_lb = guests × 1.5

Example: 30 guests for 4 hours, average crowd, 20% non-drinkers. That is 24 drinkers × 5 drinks = 120 drinks. At 50/30/20 beer, wine and cocktails: 60 beers (3 cases), 36 glasses of wine (8 bottles), 24 cocktails (2 bottles of spirits and 8 litres of mixers), plus 45 lb of ice.

• The two-in-the-first-hour, one-per-hour-after rule is the standard catering estimate. It holds well for a typical social gathering and less well at either extreme — a wedding reception with a long drinks period runs higher, a family lunch lower.
• A standard drink is a 12 oz beer, a 5 oz glass of wine or a 1.5 oz shot of spirits. Serving larger measures — and most home pours are larger — increases consumption of the bottle without increasing the drink count.
• A 750 ml bottle of wine gives 5 standard glasses and a 750 ml bottle of spirits gives 16 shots. Generous home pours reduce both, often to 4 and 12 respectively.
• The non-drinker default of 20% suits a mixed adult gathering. Adjust it up for a daytime family event and down for a late party where nobody is driving.
• Mixers are estimated at one litre per three cocktails, which suits highballs. Cocktails with juice or a large mixer component need considerably more.
• Ice at 1.5 lb per guest covers chilling and serving. In hot weather or for an outdoor party, double it — ice is the single most under-bought item at any party.
• Non-alcoholic drinks are estimated separately and generously, because drinkers take water and soft drinks between rounds too.
• Nothing here is advice about how much anyone should drink. It is a shopping estimate.