Tool
Event wine planner
A provisioning estimate for a host: how many bottles to buy for a given number of guests over a given number of hours.
The figures here answer “how much should I buy so I do not run out”. They are not a suggestion about how much anyone should drink, and the planning rates used are conventional catering assumptions rather than recommendations. Provide water and alternatives, and never assume a guest is drinking.
Result
About 16 bottles
How this was worked out
Formula
bottles = ⌈(guests × proportion drinking × glasses per person × pour size) ÷ bottle volume⌉
Where
- G = 20 — Guests. Total number of people attending.
- d = 0.75 — Proportion drinking wine. The share of guests likely to drink wine rather than something else. Worth adjusting — it varies enormously by occasion.
- h = 4 hours — Duration. How long wine will be served.
- f = 1.5 glasses — First-hour rate. Conventional catering planning figure. Consumption is typically higher in the first hour.
- l = 1 glasses — Later-hour rate. Planning figure for each hour after the first.
- p = 175 ml — Pour size. Serving size per glass.
- V = 750 ml — Bottle volume. Size of the bottles you are buying.
Steps
- Guests drinking wine: 20 × 0.75 = 15 = 15 people
- Glasses per drinker: 1.5 + (4 − 1) × 1 = 4.5 = 4.5 glasses — The first hour is counted separately because consumption is typically front-loaded at an event.
- Total glasses: 15 × 4.5 = 67.5 = 67.5 glasses
- Total volume: 67.5 × 175 ml = 11812.5 ml = 11812.5 ml
- Convert to bottles: 11812.5 ÷ 750 = 15.75 = 15.75 bottles
- Round up: ⌈15.75⌉ = 16 = 16 bottles — Rounded up, because running out is the failure mode a host actually cares about.
What this assumes
- This is a provisioning estimate for buying, not a target for anyone to drink. Guests drink what they choose to drink.
- Consumption rates are conventional catering planning figures, not health guidance.
- Assumes wine is available throughout and that other drinks are also on offer.
Where it stops being reliable
- Real consumption varies enormously with the occasion, the time of day, whether food is served and who is driving.
- A daytime lunch and a late-evening party with the same guest list will not consume similar amounts.
- Unopened bottles usually keep, so erring slightly high costs little.
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