Interview Questions › Guesstimate

Estimate how many pizzas are sold daily in New York City

Estimate the total number of whole pizzas (or equivalent whole pies) sold on an average day across the 5 boroughs of New York City.

Context

Consider NYC's resident population (8.5M), daily commuters/tourists (~1.5M), and pizza pizzeria density.

Clarifying questions to ask first

• Are we counting whole pies only or converting individual slices into whole pie equivalents (8 slices = 1 pie)?
• Does this include supermarket frozen pizzas or freshly made pizzeria pies only?

How to approach it

1. Compare Demand-Side Approach (Population × Consumption Frequency) vs Supply-Side Approach (Pizzeria Count × Daily Pies Sold)
2. Estimate resident population (8.5M) and percentage eating pizza on any given day (~4-6%)
3. Factor in slice shops vs whole pie delivery vs sit-down restaurants
4. Sanity check against ~2,000 pizzerias in NYC

Framework: Demand-Side: (NYC Population + Tourists) × Daily Pizza Eaters × Slices per Person / 8 Slices per Pie

Sample answer

• Total effective daily population: 9.5M (8.5M residents + 1M tourists/commuters)
• Average New Yorker eats pizza ~2 times per month -> ~6.6% eat pizza on any given day
• ~630,000 daily pizza eaters consuming avg 2.5 slices = ~1.57M slices = ~200,000 whole pies/day
• Supply Check: 2,000 pizzerias × 100 pies/day = ~200,000 pies/day

1. Demand calculation: 9.5M × (24 pizza meals/year / 365 days) = ~625k people/day
2. 625k people × 2.5 slices = 1.56M slices / 8 slices/pie = ~195k whole pies
3. Supply cross-check matches at ~200k pies

Executive estimate: ~200,000 whole pizzas (or slice equivalents) sold daily in NYC, generating ~$4M in daily sales across ~2,000 pizzerias.

What interviewers look for

• Demand vs Supply Methodology
• Daily Consumption Rate Assumption
• Pizzeria Capacity Modeling
• Reconciliation of Slices to Whole Pies