Party food calculator
How much food, drink, ice and cake to buy. Pick your party, enter your guests, and the shopping list updates as you type.
Festidy's plan uses the same amounts and updates them as RSVPs come in.
Make my party planHow we calculate
- Pizza: 2 slices per kid and 3 per grown-up (1.5 for kids 5 and under), 8 slices to a large pizza, rounded up.
- Plates, cups, napkins: 2 plates, 2.5 cups and 3 napkins per guest, counted separately.
- Kids' drinks: juice boxes, pouches or lemonade, 1 per kid an hour. The party length is the planner's: 2 hours for a kids' birthday, 2.5 for a baby shower, 3 for the rest.
- Grown-ups' drinks: 2 in the first hour, then 1 an hour (soda, sparkling water, beer or wine).
- Water: counted on its own, 8 oz per kid an hour and 4 oz per grown-up an hour, shown as small (8 oz) bottles and as gallons (a gallon is 16 cups). The hot-day chip adds half again.
- Ice: about 2 lb per guest. The hot-day chip doubles it.
- Fruit, veg and chips (kids' parties): about 1 cup of fruit or veg per guest, and about 3 oz of chips per kid.
- Cake: one serving per guest. Up to 12 is an 8-inch round or a dozen cupcakes, up to 24 a quarter sheet, up to 48 a half sheet, and more than that is one half sheet per 48.
- Grown-up parties: about 1 lb of food per guest. Seats are the share of guests sitting at once: about 90% at a baby shower, 45% at a graduation open house, and 60% at a birthday or house party.
- Only know the total? Festidy assumes about 6 in 10 guests at a kids' party are kids.
Last updated October 21, 2026. Free, no sign-up.
New to Festidy? See how the free birthday party planner works.
Tips for buying party food
- Buy the dry goods first and the cold things last. Ice, cake and anything that melts go in the cart on the way out.
- Round up on cups and napkins. Kids lose cups, and napkins vanish. A spare sleeve costs little.
- Ask about allergies on the invitation. Keep one safe snack ready and keep the labels from packaged food.
- Grapes and popcorn need care. Whole grapes, popcorn, nuts and hard candy are choking risks for children under 4, so cut grapes in half or skip them.
Questions
How much food for 30 guests?
At a kids' party that is about 18 kids and 12 grown-ups: 9 large pizzas, 60 plates, 75 cups, 90 napkins, 60 lb of ice and a half sheet cake. At an adult party, plan about 30 lb of food.
How much food do I need for a kids' birthday party?
For 12 kids and 8 grown-ups: 6 large pizzas, 40 plates, 24 kids' drinks, 24 grown-ups' drinks, 32 small waters, 40 lb of ice, 20 cups of fruit or veg and a quarter sheet cake.
How much food per person for a party meal?
About 1 lb of food per grown-up guest for a sit-down or buffet meal. For kids' parties, count pizza instead: 2 slices a kid, 3 a grown-up.
How many drinks per person for a party?
Kids get 1 flavored drink an hour, so 2 in a 2-hour party. Grown-ups get 2 in the first hour and 1 an hour after, so 4 in 3 hours. Water is counted on top of that.
How much cake for 30 guests?
A half sheet cake, which serves up to 48 in our plan, or 3 dozen cupcakes. A quarter sheet stops at 24. Our cake size calculator has the pan sizes.
How many plates, cups and napkins for a party?
Per guest, 2 plates, 2.5 cups and 3 napkins. For 20 guests that is 40 plates, 50 cups and 60 napkins.