Wedding Alcohol Calculator: How Much Booze You Actually Need

How much booze to buy for a wedding is a maths problem dressed up as an emotional decision. Caterers solve it with one rule: one standard drink per guest, per hour, front-loaded because the first hour always hits harder than the rest. Everything else is just that number multiplied out against your guest list and your bar tab.

The napkin maths

Two drinks in hour one, then one drink every hour after that. Split it 50/30/20 across wine, beer, and spirits. Do that, and you've basically got the whole system.

Take a wedding with 100 drinking guests over five hours. Not 100 people on the invite list, 100 people who'll actually have a glass in hand, which is a smaller number than you think and matters more than you'd guess.

Two drinks in the first hour, one for each of the remaining four, and you land on 6 standard drinks per guest. Multiply that by 100 and you get 600 standard drinks for the night.

Split 50/30/20, and wine takes 300, beer takes 180, spirits take 120.

Now convert. A 750ml bottle of wine holds about 7.5 standard drinks, so 300 divided by 7.5 gets you 40 bottles. A carton of beer, 24 cans, holds roughly 24 standard drinks, so 180 divided by 24 rounds up to 8 cartons. A 700ml bottle of spirits holds somewhere between 16 and 17 drinks depending on the pour, so 120 divided by 16 lands around 7 or 8 bottles.

That works out to forty bottles of wine, eight cartons of beer, and seven or eight bottles of spirits. Add sparkling for the toast, which gets its own maths further down, because toasts are their own weird little animal.

Skip the arithmetic

Here's the same formula already run for the guest counts most people are actually planning around, assuming a standard five-hour reception and the 50/30/20 split.

• 50: wine (bottles) 20, beer (cartons) 4, sparkling for toast (bottles) 7, spirits (bottles) 4
• 75: wine (bottles) 30, beer (cartons) 6, sparkling for toast (bottles) 10, spirits (bottles) 6
• 100: wine (bottles) 40, beer (cartons) 8, sparkling for toast (bottles) 14, spirits (bottles) 8
• 150: wine (bottles) 60, beer (cartons) 12, sparkling for toast (bottles) 20, spirits (bottles) 11
• 200: wine (bottles) 80, beer (cartons) 16, sparkling for toast (bottles) 27, spirits (bottles) 15

Sparkling assumes one toast pour per guest, plus a little cushion for spills, not free pouring bubbles all night. If the reception's running long, add 15 to 20% per column for every extra hour. Running short, take the same amount off.

Your crowd will wreck this ratio, and that's fine

The 50/30/20 split works as a starting point. It won't survive contact with your actual guest list, and honestly it shouldn't.

Got a beer crowd? Tradies, footy mates, a groom's side that's never once ordered a chardonnay? Shift to 40% wine, 40% beer, 20% spirits, buying an extra carton and cutting a couple bottles of wine.

Summer wedding changes the physics entirely. Nobody wants a warm scotch at 32 degrees in Sydney in January. Heat pushes beer and light whites up, drags spirits down. Try 40% beer, 45% wine, 15% spirits.

Winter's the opposite. Reds and spirits climb when the temperature drops. Push wine to 45% (heavier on reds), beer down to 25%, spirits up to 30%.

Running a full bar for cocktail hour only, then switching the reception itself to table service wine and beer? Calculate that cocktail hour on its own using the 2-drinks-in-hour-one rate, then apply the standard hourly rate to whatever's left of the night.

Got a guest list where a third or more don't drink, for religious reasons, personal ones, whatever the reason is, it's not your business to ask? Don't run the standard formula against your full headcount and hope the numbers self-correct. Work off your real drinking headcount instead, and actually think through your non-alcoholic lineup rather than leaving one sad jug of orange juice at the end of the table like it's an afterthought.

Got a long gap between ceremony and reception, common enough in Australia when the ceremony's at 1pm and nobody's eating dinner till 6? If you're pouring drinks during that gap, count those hours separately with the same hourly rule. Guests who've been drinking since 2pm are part of your reception total whether you planned for them or not.

The toast is not the whole bottle

Toast pours run small, 90 to 100ml, which gets you 7 to 8 pours per 750ml bottle. So for a toast-only pour, one bottle covers 7 to 8 guests. That's where the numbers in the table above come from.

Planning to pour sparkling all night instead of just for the toast? Different maths entirely. Fold it into your wine total using the standard 7.5-drinks-per-bottle rule, not the toast-pour numbers. Mixing these two calculations up is the single most common reason couples run dry on bubbles by 9pm, standing there with an empty bucket of ice wondering what happened.

Water, soft drink, and the ice you forgot about

Everyone forgets this part until 40 people are circling one warm jug of lemonade wondering where the water went.

Budget 1 to 2 non-alcoholic drinks per guest, per hour, on top of everything above, not instead of it. Even the heaviest drinkers want water or a soft drink at some point across a five-hour reception, especially if it's outdoors in summer.

Water needs to be actually available, not one jug sitting on the bridal table like a museum piece. Aim for a jug per table of 8 to 10 guests, refilled at least once.

Ice is the quiet budget killer nobody accounts for. Caterers work off roughly 1kg of ice per guest for a full-day event, covering both chilling drinks and serving them, more if you're using an esky instead of a fridge. For 100 guests that's 100kg of ice, which sounds like a joke until you remember it melts, gets used twice, and a half-warm esky of beer at 6pm is not the vibe anyone's going for.

BYO, corkage, and the venue trade-off

This is where actual money gets decided, and there's no universal right answer here, just trade-offs worth running the numbers on before you sign anything.

BYO with corkage: some venues let you bring your own alcohol and charge a fee per bottle or per person, anywhere from around $5 to $25 or more depending on the venue and whether it's wine, beer, or spirits. Do the maths before assuming it's the cheap option. A $15 bottle plus $10 corkage puts you at $25 a bottle, which might beat what the venue charges to supply and pour it themselves, or might not.

Sale-or-return: a handful of Australian bottle shops, mostly the bigger chains, will let you buy in bulk for a wedding and return unopened, undamaged bottles afterward for a refund. Ask about this specifically when placing a bulk order, before you buy, not after. Not every store offers it and not every product line qualifies.

Dry-hire venues hand you an empty space and let you bring everything yourself, alcohol included. Usually the cheapest option per bottle, and also the most work: you're sourcing the alcohol, the ice, the glassware, and RSA-certified staff to actually pour it. That last part isn't optional, since it's the law, not a suggestion.

Licensed venues with beverage packages bundle it all into a per-guest or per-hour rate, RSA staff included. You'll pay more per standard drink than BYO nearly always costs, but you're buying your way out of the logistics headache, and for plenty of couples that trade is worth every dollar. There's no shame in paying someone else to deal with the esky.

BYO plus corkage tends to win on raw cost if you've got the time to source and haul everything yourself. A venue package wins on convenience and predictability. Neither one's the objectively correct answer; they're just trading money for time, so pick whichever one you're actually short on.

None of this works if your headcount's wrong

Here's the mistake that trips up nearly every couple doing this for the first time: running the maths against the invite list instead of the guest list that's actually going to show up and drink.

Those two numbers are almost never the same. You invite 150 people. Fifteen decline. Ten are kids. Eight more don't drink, for their own reasons that are frankly none of your business. Suddenly your "150-guest wedding" is a 117-person drinking event, and every bottle count above shrinks along with it.

Subtract the kids first; they're not drinking your pinot, one hopes. Subtract the known non-drinkers next, the ones who've told you outright or who you already know don't touch it. Then work off confirmed RSVPs, not the original invite list, because "invited" and "actually attending" can drift apart by 15 to 20% even in a wedding that's otherwise perfectly organised.

Which is exactly why your guest list and RSVPs need to live in one place well before you're standing in a bottle shop aisle doing mental maths on the fly. If you're still building that list, building your wedding guest list is worth a read first, because a clean list makes every calculation downstream, alcohol included, a lot less painful. WedBuild's online RSVP tool handles exactly this: guests confirm in one place, and you can slot a simple drink question right into the form, so your 50/30/20 split is based on what people said, not on a guess pulled out of thin air. WedBuild is free to start for up to 50 guests; past that it's a single one-time payment, never a subscription it.

Alcohol's rarely the only line item couples underestimate. Worth a look at the hidden wedding costs couples always forget, and if you're budgeting specifically in Sydney, the average wedding cost in Sydney gives a sense of where booze actually sits in the bigger picture.

How WedBuild Keeps the Headcount Honest

Every number on this page is a multiple of one input: how many people are actually drinking. Get that wrong and the rest of the maths is confidently wrong with it — which is why couples end up with three unopened cartons in the garage, or a bar that runs dry at nine.

WedBuild's guest list gives you the real number rather than the invite count, because it is fed by the RSVPs themselves — confirmed attendance, children flagged separately, and custom RSVP questions if you want to ask outright who is not drinking. Run this calculator off that figure rather than your invite list and the split stops being a guess. The spend then goes into the budget planner as its own category, so the bar sits next to catering instead of surfacing as a surprise on the credit card in week three.

The numbers, in AUD: the guest list, online RSVPs with custom questions, wedding website and checklist are all in the free plan for weddings up to 50 guests. Standard is A$99 paid once, which removes the guest limit and adds the budget planner and drag-and-drop seating. Pro is A$199 paid once. One-time payments, never a subscription — and since WedBuild is built in Australia, everything prices and reads in AUD.

Frequently asked questions

How much alcohol do I need for 100 wedding guests?

Roughly 40 bottles of wine, 8 cartons of beer, 7 to 8 bottles of spirits, and around 14 bottles of sparkling for the toast. That is built on 6 standard drinks per guest across a five-hour reception, split 50/30/20.

How many bottles of wine per person at a wedding?

About 0.4 bottles per drinking guest over five hours, or 1 to 2 glasses each if wine is their main pour. A 750ml bottle gets you roughly 5 glasses, so 40 bottles comfortably covers 100 wine drinkers for the night.

Is it cheaper to BYO alcohol to a wedding?

Usually, though not automatically. Add corkage and BYO can land level with, or occasionally above, a venue's package price, especially anywhere charging high per-bottle fees. Run the actual numbers for your specific venue instead of assuming.

How much sparkling wine do I need for the toast?

One bottle covers 7 to 8 toast pours at around 100ml each. For 100 guests, that is roughly 13 to 14 bottles for a toast-only pour. Pouring sparkling all night instead? Fold it into your wine total, do not treat it as a separate toast calculation.

What happens to leftover alcohol?

Unopened bottles bought through a sale-or-return deal can usually go back for a refund; confirm with the retailer before you order, since not every store or product qualifies. Anything bought outright is yours, which is reason enough to slightly under-buy rather than over-buy.

Do I need to count children and non-drinkers?

Yes, so subtract them. Pull children and known non-drinkers out of your headcount before running any of this maths. Calculating off your full invite list instead of your real drinking count is the most common reason couples end up with three unopened cartons of beer in the garage a month later.

How do I get an accurate drinking headcount before the wedding?

Take it from confirmed RSVPs, not the invite list, and flag children separately. If you want to be precise, add a custom RSVP question — WedBuild lets you ask anything at RSVP and files the answer against the guest, so "not drinking" sits next to their dietary note. RSVPs and the guest list are in the free plan for weddings up to 50 guests, and A$99 paid once above that.

Where should the bar sit in a wedding budget?

As its own line, not folded into catering — corkage, ice, glassware hire and the staff to pour it are all separate charges that arrive at different times. Give it a category in your budget with the deposit and the balance tracked against it. WedBuild's budget planner (Standard, A$99 paid once) does this with alerts when a category runs hot, and the hidden costs guide covers the rest of the ones that ambush couples late.