What this calculator does
This alcohol for party calculator turns three simple inputs, guest numbers, how long the event runs, and how many drinks each person is expected to have per hour, into a total drink count to shop or cater against. It is a starting estimate rather than a fixed rule, since drinking pace varies hugely by event type, culture and the specific mix of guests.
The drinks-per-person-per-hour rate is left fully editable rather than fixed at any one figure, because a relaxed dinner party, a long wedding reception and a short cocktail hour all call for very different assumptions. Entering a rate that matches the actual event gives a far more useful number than any single default ever could.
The formula
Multiply the number of guests by the length of the event in hours, then by the drinks-per-person-per-hour rate, to get the total number of drinks needed across the whole party.
| Term | Meaning |
|---|---|
| Guests | The number of people expected to be drinking at the event. |
| Event length | How many hours the party or event runs for. |
| Drinks per person per hour | The assumed average pace of drinking per guest, an editable input rather than a fixed rate. |
The inputs explained
| Field | What to enter |
|---|---|
| Number of guests | The number of guests you expect to be drinking, not the total headcount if some will not be drinking. |
| Length of the event (hours) | The total length of the event, in hours, that drinks need to be available for. |
| Drinks per person per hour | How many drinks, on average, each guest is expected to have per hour. A relaxed gathering might sit around 1; a longer, livelier event might run higher. |
When to use it
Planning a birthday party or barbecue
Entering the expected guest count and roughly how many hours people will be there gives a total drink count to shop for, before working out how that splits across beer, wine and spirits.
Catering a wedding reception
A longer event with a higher expected drinking rate, such as an evening reception with a bar open for several hours, needs a noticeably larger total than a short afternoon gathering with the same guest count.
Adjusting for a lighter or heavier-drinking crowd
Changing only the drinks-per-person-per-hour rate, while keeping guest count and event length the same, shows how sensitive the total is to that one assumption, which is worth testing before finalising an order.
Worked examples
Every figure in the tables below is produced by this page’s own calculator at build time, so the numbers and the tool always agree. Select any row to load that scenario.
How does the total change with event length, for 40 guests?
A fixed 40 guests, at 1 drink per person per hour, across a range of event lengths.
| Event length | Total drinks needed | Average drinks per guest |
|---|---|---|
| 2 hours | 80 | 2.0 |
| 3 hours | 120 | 3.0 |
| 4 hours | 160 | 4.0 |
| 5 hours | 200 | 5.0 |
| 6 hours | 240 | 6.0 |
| 8 hours | 320 | 8.0 |
How does the total change with guest count, for a 4 hour party?
A fixed 4 hour event, at 1 drink per person per hour, across a range of guest counts.
Questions
What drinks-per-person-per-hour rate should I use?
There is no single correct figure; it depends heavily on the event, the guest mix and local drinking culture. A commonly cited starting point for a standard party is around 1 drink per person per hour, but adjust it up or down for the specific event before relying on the total.
Does this account for guests who do not drink?
Only if you account for it in the guest number entered. Using the number of guests who are actually expected to drink, rather than the full headcount, gives a more accurate total than assuming everyone drinks at the same rate.
How do I turn the total drinks figure into an actual shopping list?
Divide the total by how many servings come out of each container you plan to buy, such as servings per bottle of wine or drinks per case of beer, to convert the raw drink count into bottles or cases to purchase.
Should the rate be the same for the whole event?
Not necessarily. Drinking pace often peaks earlier in an event and tapers off later, so a single average rate is a simplification; for very long events, it can help to estimate a heavier first few hours and a lighter rate afterwards separately.
To work out a spirit's strength after diluting it for cocktails, see the alcohol dilution calculator. For how UK standard units of alcohol add up per drink, see the alcohol units calculator.