How the Party Drink Calculator works
This tool turns a simple planning rule into a concrete shopping list. Bartenders and caterers use a well-worn rule of thumb: expect about one drink per guest per hour, and count the first hour as two drinks because people tend to arrive thirsty and drink faster before they settle in and eat.
The core estimate is:
- Drinking guests = total guests × (percent who drink ÷ 100)
- Total drinks = drinking guests × (party hours + 1) — the "+1" is the extra first-hour drink
So a 4-hour party has 4 + 1 = 5 drinks per drinking guest: two in the first hour, then one each for hours two, three, and four.
Turning drinks into bottles and cans
The total is split by your beer / wine / liquor percentages, then each share is converted into things you can actually buy using standard serving sizes:
- Beer: one 12 oz can or bottle = one drink, so beer drinks map 1:1 to cans.
- Wine: a 750 ml bottle holds about 25.4 oz, which pours five 5 oz glasses. Wine drinks ÷ 5 = bottles.
- Liquor: a 750 ml bottle is about 25.4 oz; at the standard 1.5 oz pour that is roughly 16 cocktails per bottle. Liquor drinks ÷ 16 = bottles (you will also need mixers and ice).
Bottle and can counts are always rounded up — you cannot buy two-thirds of a bottle, and running out mid-party is worse than a small surplus.
Common reference points
- A case of beer is 24 cans; a half-barrel keg holds about 165 twelve-ounce pours.
- Plan on 1–2 lbs of ice per guest for chilling and drinks.
- Roughly 1 liter of mixers per three cocktail drinkers is a common starting point for soda, juice, and tonic.
Frequently Asked Questions
How many drinks should I plan per guest?
Use one drink per guest per hour, counting the first hour twice. For a 4-hour party that is about 5 drinks per drinking guest. Multiply by the number of guests who actually drink (this calculator lets you set that percentage) rather than your full headcount.
How many glasses are in a bottle of wine?
A standard 750 ml bottle holds about 25.4 oz, which is five 5 oz pours. A case of 12 bottles therefore covers about 60 glasses of wine.
How many cocktails does a bottle of liquor make?
At the standard 1.5 oz pour, a 750 ml (about 25.4 oz) bottle makes roughly 16 drinks. A 1.75 L handle makes about 39. Remember to buy mixers, garnishes, and plenty of ice alongside the spirits.
Is it better to over- or under-buy?
Over-buy slightly. Unopened beer, wine, and spirits keep for future occasions, and most stores accept returns of unopened cases. Running dry an hour before the party ends is the outcome to avoid, so this tool rounds bottle and can counts up.