When it comes to Netflix’s viewership numbers, we’re all blindfolded like Sandra Bullock in Bird Box, the Netflix thriller that apparently everyone – except me – watched over the holidays. There are no Nielsen or Comscore numbers to confirm or deny whatever Netflix chooses to publish about its audience figures. And, frankly, given that they aren’t vying for advertising dollars (yet?), who can really blame them for holding their House of Cards so close to their vest?

So, when Reed Hastings, Ted Sarandos, and Company boasted about the 45 Million Netflix accounts who watched Bird Box last week, the media punditry pounced, with reactions ranging from awe to incredulity. Even people who took Netflix at their word (count me among them) assumed there was some fuzzy math involved. In the end, we’ll likely never know for sure.

But, just for fun, let’s see how close we can get to the truth using CivicScience data, which has historically been pretty reliable at sizing Netflix numbers.

Guesstimating the Actual U.S. Audience

Our latest figures suggest that 59% of U.S. adults live in a household with a Netflix account, a number that is consistent with other third-party estimates. Based on an online adult population of roughly 230 Million, that means approximately 136 Million Americans aged 18+ have access to Netflix in their homes.

The challenge, of course, is reconciling the difference between “users” and “accounts” or “households”. At the most recent count, Netflix has approximately 58 Million subscriber accounts in the U.S. and 79 Million outside of the U.S.

Looking at U.S. figures only, we know that 72% of Netflix households have more than one user on the account. Combining CivicScience data with Netflix reports, we can also estimate that the average U.S. Netflix account has 2.34 adult users (136 Million people / 58 Million accounts).

That means if Netflix’s numbers are to be believed, way more people than accounts watched Bird Box. But how many?

If you start with the 45 MM “account” figure publicly reported, nearly 1/3rd of all 137MM global Netflix households watched Bird Box. Making a huge (*) assumption that Bird Box viewership was proportional between U.S. and non-U.S accounts, we could estimate that 19.1 Million (1/3rd of 58 Million) U.S. households watched the movie. Multiply that by the 2.34 user-per-account figure and we get a number of 44 Million people in the U.S. who may have watched the movie.

That would rank Bird Box – after Jurassic World: Fallen Kingdom and ahead of Deadpool 2 – as the 5th most-watched movie release of 2018.  Or, if you multiply 44 Million by the average movie ticket price of $9, Bird Box would have theoretically grossed over $396 Million in theaters. Of course, that presumes as many people would have wanted to see it if it required leaving their couch. Probably not.

Beware the Assumptions(*)

There are a ton of reasons why these numbers could be off. First, it’s possible and even likely that the 45 Million account viewers came disproportionately from U.S.-based subscribers, given language barriers, popularity of stars like Sandra Bullock, etc. Second, we’re using CivicScience data from the past 30 days, while the latest official numbers on Netflix accounts were reported in Q3 of last year. We can assume that 58 Million U.S. account number is larger today. In either of those cases, the U.S. viewer numbers might be even higher than 44 Million people.  

On the other hand, just because the average Netflix household has 2.34 users doesn’t mean the movie was viewed by 2.34 people in each household. It’s probably safer to bet that some number greater than 1 but less than 2.34 people per household watched the film – which could bring our 44MM estimate down considerably.  

But for now – and just for fun – let’s assume those potential errors cancel each other out. The only people who can ever tell us we’re wrong are the good people at Netflix. And we won’t have to worry about that. They love blindfolds.  

And Finally, For Good Measure

For even more fun, we ran a question to a representative sample of over 1,700 U.S. adults, asking whether or not they watched Bird Box. These were the results:

Do you know what 19% of 230 Million U.S. adults adds up to? 43.7 Million.

Probably just a coincidence.