How Many Drinks for a Party? A Simple Formula

The one-drink-per-hour rule

The simplest way to plan is to assume each guest has about one drink in the first hour and one for every hour after. Guests tend to drink a little more early on and slow down later, so this evens out across a whole evening. Multiply the number of drinking guests by the length of the party in hours to get your baseline total.

For a 3-hour dinner with 12 people who drink, that is about 36 drinks. For a long 5-hour party with 30 guests, it is closer to 150. Always round up: leftover unopened bottles keep, but running dry mid-party does not. Buying from stores that take back unopened stock removes the risk of over-ordering entirely.

Splitting beer, wine and spirits

Once you know the total, split it by type. A dependable default is 50% beer, 30% wine and 20% spirits, but read your guests: a summer barbecue leans toward beer, a dinner toward wine, and a cocktail evening toward spirits. Ask about preferences when you invite, and keep a couple of alcohol-free options that feel like a treat, not an afterthought.

Then turn quantities into shopping units. A standard 750 ml bottle of wine pours about 5 glasses, and a 750 ml bottle of spirits gives roughly 16 single measures. Beer is easiest by the can or bottle, one per serving. For every drinking guest, plan at least two bottles of water and a soft drink or two across the night.

Serving responsibly

Buying enough is only half the job — pacing matters more. Serve food throughout, never just at the start, since eating slows alcohol absorption. Keep water and soft drinks visible and easy to reach so guests naturally alternate. Offer to arrange rides or taxis, and never let anyone who has been drinking drive home.

A calculator gives you a solid shopping list, but real gatherings vary. A young crowd on a Saturday drinks more than a mixed family lunch; a hot day means more water than you think. Treat the numbers as a starting point, buy a little extra of the crowd-pleasers, and you will never be caught short.

Frequently asked questions

How many drinks per person for a 4-hour party?

Plan on about four drinks per drinking guest for a 4-hour party, following the one-per-hour rule. For 20 guests that is roughly 80 drinks. Round up and keep extra water and soft drinks on hand.

How many glasses in a bottle of wine?

A standard 750 ml bottle of wine pours about 5 glasses of 5 oz each. So a case of 12 bottles serves roughly 60 glasses — handy for scaling a big party quickly.

What if some guests don't drink alcohol?

Estimate the share of non-drinkers and shift their portion to water, soft drinks and interesting alcohol-free options. As a rule, provide at least as many non-alcoholic servings as alcoholic ones so everyone is well looked after.

Should I buy more or less than the calculator says?

Round up. Unopened bottles and cans keep for the next occasion, and many stores take back sealed stock, so a small surplus costs little. Running out mid-party is the one outcome worth avoiding, so err on the generous side.