How much alcohol for a party?
The standard planning rule: one drink per guest per hour. About 20–25% of guests won't drink at all, and a few will have more than one an hour — it evens out. From there, split the drinks by bar style and convert to bottles.
Bottle math
- Beer: a 12 oz serving per drink; a 12-pack = 12 drinks, a case = 24.
- Wine: a 750 ml bottle pours ~5 glasses (5 oz each). A bottle per two guests over an evening is a common heuristic.
- Spirits: a 750 ml bottle of 80-proof pours ~16 standard 1.5 oz shots — enough for 15–16 cocktails.
- Champagne toast: a 750 ml bottle pours ~6 flutes, so one bottle covers 6 guests.
Never forget the non-alcoholic side
Plan 1–2 non-alcoholic drinks per guest (water, soda, sparkling water) and roughly 1.5 lb of ice per guest. For a cocktail party, add mixers at ~0.5 qt per guest (tonic, soda, juice, vermouth etc.). These are the items people run out of first — not the alcohol.
Adjust for your crowd
Weddings with mostly family: lean wine-heavy and expect lighter consumption. College reunions: beer-heavy and round up. If in doubt, buy on the lower estimate and have a backup case ready — stores sell beer cold on the day, but nobody wants to be the host who ran out at 9 PM.