You have booked the venue, confirmed the guest list, and chosen your bar style, but now you are staring at a spreadsheet trying to work out exactly how many bottles of prosecco, pints of lager, and measures of gin you need to order. Get it wrong and you are either pouring money down the drain on unopened stock or watching your guests queue at an empty bar by 9pm. Estimating drinks per head is one of the trickiest parts of event planning, and it is the question Viva Bar Hire gets asked more than almost any other.
The Golden Rule: It Is Never One Drink Per Person Per Hour
The old industry rule of thumb suggests one drink per guest per hour, but anyone who has actually been to a wedding or birthday party knows that figure is wildly oversimplified. The first hour of any event, particularly during a reception drinks window, tends to see much higher consumption. Guests arrive, they are socialising, and they are thirsty. You should budget closer to two drinks per person for that opening hour, then scale back to roughly one to one and a half drinks per hour for the rest of the evening.
For a typical five-hour evening reception with 100 guests, that means you are looking at somewhere between 550 and 700 drinks in total, not the neat 500 that the one-per-hour formula would suggest. That difference of 50 to 200 drinks is the gap between a bar that runs smoothly and one that runs dry during the last dance.
Factors That Push Your Numbers Up or Down
Every event has its own drinking personality, and experienced bar teams learn to read the room before the first glass is poured. Here are the variables that matter most:
- Time of year. Summer events skew towards lighter, longer drinks like gin and tonic, Pimms, and prosecco. Winter events see more red wine, whisky, and rich cocktails. Summer guests also tend to drink more overall because of the heat.
- Demographic. A corporate awards dinner with senior executives will have different consumption patterns to a 30th birthday house party. Neither is better or worse, but your ordering should reflect reality, not wishful thinking.
- Food service. A sit-down three-course meal slows drinking considerably compared to canapes or no food at all. If your caterer is serving a substantial meal, you can safely reduce your per-head estimate by around 15 to 20 percent during the dining window.
- Free bar versus cash bar. This is the single biggest variable. A fully hosted bar will see consumption rise by 30 to 50 percent compared to a pay-per-drink setup. Many clients opt for a hybrid approach, offering a free drinks reception and wine with dinner before switching to a cash bar for the evening, which keeps budgets manageable without leaving guests feeling short-changed.
- Duration. An afternoon garden party running from 2pm to 6pm is a very different proposition to an all-night wedding reception finishing at midnight. Longer events do not scale linearly because consumption naturally tapers as the evening goes on.
A Realistic Breakdown for 100 Guests at a Wedding
Weddings are the event type where getting quantities right matters most, because the emotional stakes are high and the budget is already stretched. For a fairly standard timeline of welcome drinks at 3pm, dinner at 5pm, and evening party until midnight, here is a realistic starting point for 100 guests:
- Welcome drinks: 200 glasses of prosecco, Pimms, or a signature cocktail, allowing two per person with a small buffer.
- Wine with dinner: 30 to 40 bottles, split roughly 60/40 white to red in summer or 50/50 in winter. That gives each guest around two to three glasses.
- Evening bar: 400 to 500 drinks across beer, spirits, cocktails, and soft drinks. Around 10 to 15 percent of your guests will be drinking soft drinks or water only, which helps offset the heavier drinkers.
- Soft drinks and water: Budget for at least 50 litres of water and 30 to 40 soft drinks. This is the category most often underestimated, especially at summer weddings.
These figures assume a mixed crowd of moderate to social drinkers. If you know your crowd leans one way or the other, adjust accordingly and do not be embarrassed about it. Your bar team would far rather have an honest conversation about your guests than discover the reality at 10pm.
What Happens to Leftover Stock
One of the biggest anxieties around over-ordering is waste. With a staffed mobile bar service, this is largely handled for you. Professional bar hire companies bring stock based on experience and consultation, and any unopened bottles are typically not charged. This is one of the key advantages of working with a supplier rather than buying everything yourself. You get the benefit of their experience without carrying the financial risk of 15 unopened bottles of sauvignon blanc.
If you are using a self-serve setup like Viva Bar Hire's Bar in a Box, the stock is yours to keep. In that case, it is worth erring on the side of slight over-ordering. Leftover wine and spirits do not go off, and you will thank yourself at Christmas when the drinks cabinet is still full.
The Smartest Thing You Can Do Is Talk to Your Bar Team Early
Quantity planning is not something you should leave until the week before your event. The earlier you have a conversation with your bar provider, the better they can tailor recommendations to your specific guest list, venue, timeline, and budget. A good bar team has seen hundreds of events and can spot the patterns that a spreadsheet cannot.
Viva Bar Hire offers free consultations for exactly this reason. Whether you are planning a staffed cocktail bar for a corporate gala, a prosecco station for a summer garden party, or a self-serve Bar in a Box for an intimate celebration, their team can walk you through the numbers so you order with confidence. Visit vivabarhire.co.uk to start the conversation and take the guesswork out of your next event.