Everything about Game of Thrones is big. Like epic big. The biggest battles. The biggest cast. The most people lit on fire at one time. Giant sets pieces and, well, giants.

This has paid off in epic ratings, too. Game of Thrones is HBO’s most watched show, and the most watched scripted show on TV, this year.

Presumably, then, HBO has generated record profit from this TV series, too. But while I could provide links to all the facts above, I can’t tell you if this is the case. I assume it is, but frankly no one knows. That’s because how much money a TV series makes is a closely guarded secret by HBO, like it is with most studios. I tried to find if anyone had ever estimated this, and as far as I know they haven’t.

Fine. Like Oberyn Martell fighting The Mountain, if you want something done right you gotta do it yourself. I used to build these types of models and estimates for a major streaming company, so I’ll make my own estimate. Hopefully, my head doesn’t explode in the process (like the Red Viper’s did).

Some cautions before I unveil my results. Some things were easier to find out than others. There have been a lot of leaks about episode production costs; many fewer leaks on merchandise sales, for example. To fill in the gap, I scoured the internet to find out what has been revealed, what tidbits of revenue we do know, and some other details. If I couldn’t figure it out, well, I used my best estimates and sometimes just guesses. But educated guesses.

Add it up, and from 2011 to 2019 (and beyond), over eight seasons I project that HBO has made/will make…

…$2.28 billion on Game of Thrones.

In other words, a profit of roughly $285 million per season. That’s easily one of the most profitable TV series of all-time.

That top line number, though, only tells some of the fun story. For the gory details, I’ll walk you through my estimated budget. If you’d like to know more about the calculations that went into this article, check out my series of articles explaining the TV business through a battle for “the next Game of Thrones” between Amazon, Netflix and HBO.

Revenues from Subscriptions HBO starts to make up the money for all those battle scenes and actors by selling subscriptions. HBO has three main ways it sells these subscriptions: in the US through cable and satellite providers, internationally through their pay TV providers, and now digitally direct-to-consumers through its HBO Now service. (It also licenses content to other premium pay TV channels, but I’ll get to that next.) The bulk of the value of GoT comes from this initial window. GoT is clearly great at driving new subscriber growth, but quantifying that is pretty hard, because it involves determining how much value any individual subscriber puts on GoT. As a result, that pot of money is both substantial, and probably less than you think. Let’s go over what we know. First, subscriber and profit growth. HBO had been flat in subscriber growth from about 2010 to 2011, even declining between 2009 and 2010. Then, in 2011, Game of Thrones came and domestically (the United States and territories) HBO went from 39.4 million subscribers in 2011 to 54 million subscribers by 2017. (Those numbers include both HBO and Cinemax subscriptions, and digital.) Internationally—primarily, Latin America, Asia and Central/Eastern Europe—the sub growth was similarly impressive going from 53 million subscribers to 88 million. Digitally, they launched HBO Now in 2015 that currently reaches more than 5 million subscribers. (All these numbers come from formerly Time Warner’s annual reports.) And, over the same time period, HBO’s revenues increased from $4.5 billion per year in 2011 to $6.3 billion in 2017, including growth in operating income of $1.4 billion to $2.1 billion. Is it a coincidence that HBO has experienced this growth as GoT took over the collective conscious? Starting in season 1, GoT‘s ratings have gone up every year, and almost every episode. This table—using Wikipedia and news reports—shows the live and total viewership numbers by season. In short, there are now 43 million people watching GoT in just the US alone. Maybe more if some of those viewings are by families or groups. And it’s not just the US. We know this is the biggest subscription show in the United Kingdom, Australia and has experienced huge growth in Canada, Italy, Russia, Singapore and many more countries. It can be tempting to assume, then, that all of HBO’s growth is due to Thrones by itself. That’s a bit too aggressive. There’s other bad ways to try to make this determination. (The worst is simply multiplying viewers by price per month. Don’t do that. Read here for why not.) The best way is to attribute the number that the viewers (new and returning) that the show was responsible for. Then you multiply those customers by their “lifetime value” to HBO. So I made a bunch of estimates using this methodology, assuming that 10% of new US subscribers, 5% of new international subs and 50% of new digital subscribers were owed to Game of Thrones. I also gave GoT credit for keeping current subscribers “retained” at a 2% rate. (That sounds low, but in my experience is very reasonable.) Using those numbers and a bunch of other estimates—like my own customer lifetime value calculations—it got me to my estimate of the value per subscriber: Conservatively, I think that Game of Thrones alone has driven $1.9 billion in subscription value for HBO over the last 9 years or so. (And some of these benefits will carry over for a few years.)