Bar planning has one load-bearing rule — one drink per guest per hour — and everything else is arithmetic: split the total across beer, wine, and liquor, then divide by servings per bottle. Here's the full calculation with real numbers, plus the adjustments that actually matter (daytime weddings, non-drinkers, the champagne toast).
Bartenders and caterers plan on one alcoholic drink per guest for every hour the bar is open. It sounds low and isn't: averaged across a whole reception, it already includes the guests drinking three and the guests drinking zero. A 4-hour reception for 100 people is 400 drinks. For a crowd that leans boozy, use the generous variant — two drinks the first hour (arrival plus toasts), one per hour after — which gives 5 drinks per guest instead of 4.
Notice what the rule doesn't ask: what people drink, only how much. That's handled next.
Guests × drinks-per-guest. Standard rule: guests × hours. Generous: guests × (2 + hours − 1).
| Reception | Standard (1/hr) | Generous (2 + 1/hr) | 100 guests, standard |
|---|---|---|---|
| 2 hours | 2 each | 3 each | 200 drinks |
| 4 hours (typical) | 4 each | 5 each | 400 drinks |
| 5 hours | 5 each | 6 each | 500 drinks |
The default evening mix is 50% beer, 25% wine, 25% liquor. Wine-forward crowds flip to 20/50/30; beer-and-wine-only bars commonly run 60/40 with no liquor. For 400 drinks at the standard split: 200 beers, 100 glasses of wine, 100 liquor drinks.
A 750ml bottle holds 25.4 ounces. From there: wine pours at 5 oz give 5 glasses per bottle; liquor at 1.5 oz shots gives 16-17 per bottle; champagne toast pours at 4 oz give 6 flutes per bottle. Beer is one drink per bottle, 24 to the case.
Full-bar caveat: cocktails that pour 2 oz of spirit plus mixer drain a bottle in about 12-14 drinks, not 17. If your crowd orders old fashioneds, add a bottle per 150 cocktails.
Guests, hours, mix, toast, and prices — the calculator converts it all to bottles, cases, and a budget in real time.
Wedding Alcohol Calculator →At typical retail — $25 a case of beer, $12 a wine bottle, $20 a liquor bottle, $15 a champagne bottle — the 100-guest example totals 9 × $25 + 20 × $12 + 6 × $20 + 17 × $15 = $840. Venue bar packages for the same headcount typically quote $1,500-3,000, which is why buying your own is the single biggest bar saving available. Check two things in your venue contract first: corkage fees (often $10-25 per bottle, which quietly re-adds hundreds) and whether sealed leftovers can be returned — most stores and many venues allow it, which changes the "buffer" decision below.
Typically 30-40% of guests don't drink alcohol, so the honest floor is about two-thirds of the rule's total. Most couples buy the full amount anyway as buffer: leftover sealed bottles return or keep, while a bar that runs dry during the toasts does not. If you buy light, at least protect the champagne — the toast is the one pour you can't improvise.
Brunch and early-afternoon receptions run 10-20% lighter. Multiply by 0.85 and shift the mix toward sparkling wine and light beer. Evening receptions with dancing run the full estimate; late-night snacks famously trigger a second drinking wave, so don't trim for a midnight pizza hour.
One or two signature cocktails simplify the liquor math: each 750ml bottle serves about 14-15 of a 2-oz-spirit recipe, and guests drink what's offered. A single signature cocktail plus beer and wine usually cuts total liquor needs by a bottle or two versus a full bar — and it speeds the bar line, which matters more than most couples expect during the cocktail hour crush.
Plan soft drinks at one per guest per two hours — the same guests, plus the drinking ones between pours. Water is the sleeper: half-liter bottles or a water station at roughly one per guest for a summer reception. Coffee for 60-70% of guests if it's an evening wedding with a send-off. The bar gets the attention, but the non-alcoholic table is where weddings actually run out.
One drink per guest per hour over a 4-hour reception is 400 drinks: about 200 beers (9 cases of 24), 100 glasses of wine (20 bottles), and 100 liquor drinks (6 bottles of 750ml) at the standard 50/25/25 split. Add 17 bottles of champagne for a toast. That's roughly $840 at retail prices.
If wine is a quarter of the mix, each drinking guest averages one glass of wine per reception — one bottle per five guests. A wine-forward crowd drinking half their drinks as wine needs closer to two glasses each, or two bottles per five guests.
Usually yes — retail markups at venues run 2-4x store prices, so buying your own at $800-900 for 100 guests can replace a $2,000-3,000 venue package. The catch is venue corkage fees ($10-25 per bottle in many contracts), required licensed bartenders, and return policies. Run both totals before deciding.
Roughly 60-70% of a typical guest list drinks alcohol, so the true minimum is about two-thirds of the rule's total. Most couples buy the full amount anyway as buffer, since leftover sealed bottles can often be returned — and running dry during the toasts is the worse failure mode.