How Much Alcohol for a Wedding or Party? The Formula Bartenders Actually Use

Every host who has ever stocked a bar for a wedding or a big party has stood in the beverage aisle asking the same unanswerable-feeling question: how much is enough? Buy too little and you get the worst version of the night — a dry bar at 9pm, a scramble to send someone to the liquor store, guests nursing warm soda while the DJ keeps playing. Buy too much and you’ve tied up hundreds of dollars in booze that either goes home in the trunk or, worse, gets opened “just in case” and can’t be returned. The good news is that this isn’t actually a guessing game. Event planners and caterers have relied on a simple rule of thumb for decades, and once you know it, turning a guest list into a shopping list is arithmetic, not intuition.

The rule: one drink per person per hour

The industry standard planning assumption is that each drinking guest consumes about one alcoholic drink per hour of an event. It’s deliberately a round, conservative-leaning number — real consumption is lumpier than that. Guests tend to drink a bit faster in the first hour, especially if there’s a cocktail hour before dinner, and tail off as the night goes on and people eat, dance, and start thinking about driving home. But averaged across a whole event, one drink per hour per drinker is a number that has held up well enough that virtually every catering and event-planning guide still uses it.

The reason this rule is so useful is that it converts two things you already know — how many people are coming and how long the event runs — into a single number you didn’t know: total drinks needed. From there, the rest of the math is just packaging.

Why the drinker mix matters more than the headcount

Here’s the detail that trips people up: not every guest drinks, and among those who do, wine drinkers, beer drinkers and cocktail/spirits drinkers consume completely different products in completely different container sizes. A wedding with 100 guests who are mostly wine-and-beer people needs a very different order than one with the same headcount skewing toward a full cocktail bar.

So the real calculation has two layers. First, figure out how many of your guests actually drink, and split those drinkers into wine, beer and spirits/cocktail categories (your non-drinkers still matter — they’ll want soft drinks, just at a lower rate). Second, apply the one-drink-per-hour rule only to the drinking guests, then split that total across the three categories in proportion to your mix.

If your guest list skews 35% wine, 35% beer, 15% spirits and 15% non-drinkers, only the 85% who drink are consuming a drink an hour — the non-drinkers are a separate, smaller line item on the soft-drink side.

Converting drinks into things you actually buy

Once you know how many wine drinks, beer drinks and spirits drinks you need, you have to convert those into purchase units, because nobody sells alcohol by the “drink”:

• Wine: a standard 750ml bottle pours about 5 glasses. Divide your total wine drinks by 5 and round up to get bottles.
• Beer: sold by the case, and a standard case is 24 bottles or cans. Divide total beer drinks by 24 and round up for cases — but it’s worth also knowing the raw individual-can count, since you may be buying loose six-packs rather than full cases for a smaller gathering.
• Spirits/cocktails: a 750ml bottle of spirits makes roughly 17 standard 1.5oz cocktails or shots. Divide total spirits drinks by 17 and round up.

Rounding up at every step is intentional. A caterer’s rule of thumb across the industry is that running out is a genuinely bad guest experience — visible, awkward, and impossible to fix mid-event — while a few unopened bottles are, at worst, a minor cost. Most wine and liquor stores will also let you return full, unopened bottles after the event (a case or bottle you never cracked open), so the financial risk of over-buying is usually much smaller than it looks on the receipt. The one exception is kegs and some beer formats, so check your vendor’s return policy before you over-order beer specifically.

Don’t forget the ice

Ice is the most commonly under-ordered item at any bar, because it disappears into drinks, coolers and buckets faster than anyone expects. The standard rule of thumb is 1 to 1.5 pounds of ice per guest, covering both drinks themselves and pre-chilling bottles and cans before service. For a 100-guest wedding that’s 100 to 150 pounds — easy to underestimate if you’re only thinking about ice cubes in glasses and forgetting the cooler full of beer that needs to stay cold for five hours.

A worked example: 100 guests, 5 hours

Let’s put real numbers through the formula. Say you’re planning for:

• 100 guests, over a 5-hour reception
• Drinker mix: 35% wine, 35% beer, 15% spirits, 15% non-drinkers
• The standard 1 drink per person per hour rate

Of your 100 guests, 85 are drinkers (35 + 35 + 15). At one drink per hour for five hours, that’s 85 × 5 = 425 total drinks across the event. Splitting proportionally across the drinking guests:

• Wine drinks: 175 → 35 bottles of wine
• Beer drinks: 175 → 8 cases of beer (175 individual beers, if you’re buying loose)
• Spirits drinks: 75 → 5 bottles of spirits

Add 125 lb of ice (100 guests × 1.25), plus soft drinks for your 15 non-drinkers at a slightly lower pace over five hours — call it around 57 non-alcoholic drinks, whether that’s canned soda, juice, or a mocktail station.

That’s a complete shopping list built from three inputs: guest count, event length, and drinker mix — no guesswork, and no over-buying padding “just to be safe,” because the rounding is already baked into every step.

Try it with your own numbers

Every wedding and party has a different guest list, a different bar budget, and a different crowd. Plug your own guest count, event duration and drinker-mix percentages into the Wedding & Party Drinks Calculator and it will run this exact math for you — bottles of wine, cases and individual beers, bottles of spirits, pounds of ice, and non-alcoholic drinks for the non-drinkers — instantly, and it recalculates live as you adjust any number. If your event includes a batched cocktail (a pitcher of Margaritas or a punch bowl of Old Fashioneds rather than a full spirits bar), pair it with the Cocktail Recipe Scaler to get the exact ingredient quantities for your batch size, including the water dilution stirred cocktails need to taste right at scale.