Planning a party and not sure how much food to buy? You're not alone - "enough for everyone, without a fridge full of leftovers" is basically the eternal party-planning question. The good news: it comes down to guest count and a few simple per-person numbers, not guesswork.
These are the numbers to work from, per adult guest. Scale them by your headcount and you're most of the way there.
Main dish / protein: 6-8oz if it's the centerpiece of the meal (think a taco bar, pulled pork, or a pasta dish)
Sides: Two sides at roughly 1/2 cup each per person
Snacks / appetizers: 6-8 pieces per person for the first couple hours if apps are part of the spread, fewer if it's a full sit-down meal
Drinks: Plan on 2 drinks per person for the first hour, then about 1 per additional hour - a case of 24 cans comfortably covers 12-15 people for an afternoon
The per-person math holds steady, but it helps to see it laid out at real party sizes so you're not doing multiplication in the grocery aisle.
Party of 20: About 10-13lbs of main dish, 5 cups of each side, 2-3 cases of drinks
Party of 50: About 25-30lbs of main dish, 12-13 cups of each side, 5-6 cases of drinks
Party of 100: About 50-60lbs of main dish, 25 cups of each side, 10-12 cases of drinks
Whatever your numbers come out to, buy a little more than the math says - nobody wants to be the host who ran out of food an hour in. A 10-15% buffer on top of your per-person totals is a good rule of thumb, and it's usually cheap insurance: a few extra bags of chips or another pack of buns costs a lot less than the stress of running short.
No signup, no download - just enter your guest count below and see the numbers update live.
If you're planning something bigger - a full catered event - the rest of Catering Calc has tools built for that too.