Running out of wine at a dinner party is a social catastrophe. Buying three cases too many is an expensive one. Getting the wine calculation right for any event — from a casual backyard BBQ to a formal wedding reception — is more science than guesswork. Here's the formula.
Try it yourself: Use our free Wine Bottles Calculator to calculate exactly how many bottles of wine, beer, and spirits you need for any event size and duration.
The Basic Wine Calculation
The standard pour for a wine glass at a dinner or event is 150mL (a restaurant standard pour). A standard 750mL bottle of wine yields 5 glasses at this pour size.
Bottles needed = (Guests × Glasses per person per hour × Event hours) ÷ 5
Where 5 = glasses per 750mL bottle at 150mL pours
Average consumption: 1 glass per person per hour
Example: Dinner party, 12 guests, 4 hours
Total glasses: 12 × 1 × 4 = 48 glasses
Bottles: 48 ÷ 5 = 9.6 → round up to 10 bottles
Example: Wedding reception, 80 guests, 5 hours
Total glasses: 80 × 1 × 5 = 400 glasses
Bottles: 400 ÷ 5 = 80 bottles
Add 10% buffer: 88 bottles (round to 90)
Adjusting for Event Type and Guest Profile
The 1 glass per person per hour baseline is a starting point, not a universal rule. Adjust based on your guests and event:
| Event Type | Consumption Adjustment | Notes |
|---|---|---|
| Formal sit-down dinner | 0.75–1 glass/hour | Wine paired with courses slows consumption |
| Cocktail / drinks party | 1–1.5 glasses/hour | No food anchor; faster drinking pace |
| BBQ / casual lunch | 0.75–1 glass/hour | Mix of drinkers and non-drinkers |
| Wedding reception | 1–1.25 glasses/hour | Speeches slow consumption; allow for toasts |
| Corporate function | 0.5–0.75 glasses/hour | Professional context, mix of abstainers |
| Christmas/New Year party | 1.25–1.5 glasses/hour | Festive occasions trend higher |
Red vs. White vs. Sparkling: Allocating the Mix
For a mixed-preference group, a good default split is:
- Red wine: 40%
- White wine: 40%
- Sparkling / Prosecco: 20%
Adjust for season: Australians drink proportionally more white and sparkling in summer, more red in winter. If your event has specific food pairings (e.g. a seafood dinner), weight toward white. If you know your crowd skews toward red drinkers, adjust accordingly.
For weddings, sparkling wine is needed for the toast. Calculate 1 glass per person for the toast separately, then add it to your regular consumption calculation.
Beer, Spirits, and Non-Alcoholic Drinks
If you're providing a full drinks selection (wine, beer, spirits, soft drinks), wine typically accounts for about 50–60% of consumption at a dinner or wedding. Here's a fuller breakdown for a mixed event:
| Drink Type | Typical Share | Serves per unit |
|---|---|---|
| Wine (750mL bottle) | 50–60% | 5 glasses × 150mL |
| Beer (375mL can/bottle) | 20–30% | 1 serve each |
| Spirits (700mL bottle) | 5–10% | ~23 nips × 30mL |
| Non-alcoholic (soft drink, juice) | 15–20% | 2–3 serves per 1.25L |
Buying Tips: Getting the Most Value
- Buy by the case (12 bottles): Most bottle shops offer 10–15% discount on cases. Mixed cases often qualify for the same discount.
- Check the return policy: Many Australian bottle shops allow you to return unopened cases — ask before you buy. This lets you overbuy safely without waste.
- Chill white wine in advance: A standard refrigerator can only hold so many bottles. Hire a drinks fridge or use large tubs of ice for large events.
- Allow extra for guests who are wine lovers: The 10% buffer rule — always add 10% to your calculated total — exists for a reason. Running out at 9 PM is far worse than having two bottles left over.
- Consider wine on tap / kegs for large events: For 100+ guests, wine kegs (typically 10L or 20L) can be significantly more cost-effective than bottles.
Wedding Wine Calculator
For weddings specifically, here's a full allocation guide:
100-guest wedding, 5-hour reception
- Cocktail hour (1 hr): 100 × 1.25 = 125 glasses → 25 bottles sparkling
- Dinner (2 hrs): 100 × 0.75 = 150 glasses → 30 bottles (15 red, 15 white)
- Dancing (2 hrs): 100 × 1.0 = 200 glasses → 40 bottles (20 red, 20 white)
- Toasts: 100 × 1 = 100 glasses → 20 bottles sparkling
- Total wine: ~115 bottles + 10% buffer = 127 bottles
- Beer: ~100 cans/bottles, Spirits: 3–4 bottles
Frequently Asked Questions
How many bottles of wine for 20 people?
For a 3-hour dinner party with 20 guests at 1 glass per hour: 20 × 3 ÷ 5 = 12 bottles. Add a 10% buffer for 13–14 bottles. If your guests are moderate drinkers, 10–11 bottles should be sufficient.
How many glasses in a bottle of prosecco?
A 750mL bottle of Prosecco or Champagne yields 5–6 glasses at a standard 125mL flute pour (sparkling is served in smaller portions than still wine to retain bubbles). For toasts with smaller pours, you can get 7–8 glasses.
How much wine for a wedding of 50 people?
For a 50-guest, 4-hour reception: approximately 50 bottles of wine (plus 8–10 for the toast). Budget around 1 bottle per person across the whole event as a simple rule of thumb, then subtract 20–30% if your guests are lighter drinkers or if significant food is provided throughout.
What temperature should I serve wine?
White wine and Prosecco: 8–12°C (well chilled). Rosé: 10–12°C. Light reds (Pinot Noir): 14–16°C. Full reds (Shiraz, Cabernet): 16–18°C. "Room temperature" in an Australian summer can easily be 25°C+ — serve reds slightly cooler than you might think optimal; they'll warm in the glass.
Calculate your drinks order
Use our Wine Bottles Calculator to calculate exactly how many bottles you need for any event — with separate calculations for red, white, sparkling, beer, and spirits.
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