Size Facebook's Ad Business Bottom-Up From Daily Users, Ad Load and CPM
Company: Meta
Role: Product Manager
Category: Product / Decision Making
Difficulty: medium
Interview Round: Other
Make a back-of-the-envelope estimate of how much Facebook earns from advertising in a year.
```hint Segment before you multiply
What an advertiser pays per impression differs widely between countries, so one global average hides most of the answer.
```
### Clarifying Questions
- Does "Facebook" mean the Facebook app alone, or Meta's whole family of apps including Instagram, Messenger and WhatsApp?
- Should the estimate be global and for the most recent full year?
- Do you want a bottom-up model built from users and ad impressions, or is a top-down estimate from the advertising market acceptable?
### What a Strong Answer Covers
- The scope pinned down first, then a clear equation linking users, ad exposure and price
- Labeled assumptions, segmented where the variation actually lives
- Arithmetic shown step by step with consistent units
- A sanity check against an independent anchor, and which assumption moves the answer most
### Follow-up Questions
- If more time shifts to short-form video and those ads earn less per impression than feed ads, how does your estimate change?
- Which single input would you research first to narrow your range, and why?
- How would you adapt the model to estimate Instagram's advertising revenue?
Overview: A product manager estimation question asking for a back-of-the-envelope figure for Facebook's yearly advertising revenue. It tests building a bottom-up model from daily users, ad impressions and regional ad prices, labeling assumptions, keeping the arithmetic and units clean, and sanity-checking the result.