Perfect use for a Pizza Calculator! The calculation depends on several factors: appetite level (light/medium/heavy), pizza size, guest demographics (kids eat less than adults), other food available. General formula: adults eat 2-3 slices, teens 3-4, kids 1-2. Large pizza (14″) = 8 slices, medium (12″) = 6 slices. For 20 adults with medium appetite: 20 people × 2.5 slices = 50 slices ÷ 8 slices per pizza = 6.25, round up to 7 large pizzas. That’s the conservative estimate. Better formula accounting for reality: Categories: 10 adults (3 slices each = 30), 5 teens (4 slices = 20), 5 kids (2 slices = 10). Total = 60 slices ÷ 8 = 7.5 ? 8 pizzas. Pro tips: Order variety (half cheese, quarter pepperoni, quarter veggie), account for dietary restrictions (1-2 vegetarian options), consider appetites (sports team party? add 2 more pizzas), time of day (dinner needs more than afternoon snack), other food (if serving salad, wings, etc., reduce by 1-2 pizzas), guys vs mixed group (guys typically eat more). My formula: (number of people × 2.5) ÷ 8, then round up and add 1 “safety pizza.” For your 20 people: I’d order 8 pizzas. Better to have 1-2 slices leftover per person than run out (major party foul!). Leftover pizza is never wasted anyway – breakfast pizza is delicious! Price tip: many places have deals on multiple pizzas, and large is often better value per slice than medium.
