The season of ghosts and ghouls is upon us, a time when we ignore the boringly mundane threats of daylight to get all worked up over the imaginary ones hiding in the shadows. But let’s say you’re a realist, the kind of person who sneers, “That wouldn’t happen” at scary movies, or who withholds candy from trick-or-treaters until they’ve been subjected to your explanation of how ghost sightings can be attributed to psychological suggestion.

For sensible buzzkills such as yourself, Halloween can be a tad underwhelming—until now! For you, Dominik Czernia, a PhD candidate at the Institute of Nuclear Physics in Poland, has introduced the Vampire Apocalypse Calculator. This spine-tingling algorithm computes exactly how long it would take for your city to succumb to an invasion of deadly bloodsuckers, a terrifying scenario rendered in numbers dry as a mummy’s tomb. Lock the doors, dim the lights, and hear the blood-chilling tales spun by this merciless mathematical model!

With a series of fiendish numerical calculations, the Vampire Apocalypse Calculator allows you to pit a given human population against any number of vampires, gauging how long it would take before humanity triumphs over evil or is completely wiped out. As with anything that’s silly yet scientifically exacting, there are several variables to play with: You can make it so that every human who gets bitten then turns into a vampire, or make it a privilege bestowed only upon a chosen few. You can mess with the frequency of vampire attacks and allow for whether vampires are smart enough to stop gorging themselves once the population begins to dip. Most importantly, you can introduce vampire slayers into the mix, then adjust their zeal from full-time mission to something more casual and sporting. All of these factors come together in a graph that tracks the respective populations of humans, vampires, and slayers rising and falling across weeks, years, and even decades, until either man or monster wins. You can view this chart in a scale that’s linear or—if you dare gaze into the roiling black of dimensions unseen!—logarithmic.

Naturally, we couldn’t help but use the calculator to see how Texans might fare in a vampire apocalypse, which we determined using current population statistics and a few of our own assumptions. In doing so, we tried to match the calculator’s various built-in scenarios, based on popular vampire stories from movies and books, to the cities where they seemed most likely to play out. We then ran the numbers with and without slayers, to see what fighting back might do for our chances. Here’s what we found.

### Houston, population 2.313 million

We applied the “Stoker-King Model,” inspired by Bram Stoker’s Dracula and Stephen King’s Salem’s Lot, which begins with the arrival of a loner vampire who turns anyone he kills. With its higher-than-average number of cloudy days, and its ready access to residents fattened by rich world-class food, Houston seemed like the obvious choice for any vampire who’s looking to move to Texas, of all places. We also reduced the frequency of their attacks to “rare,” assuming even Dracula would sometimes find it too humid to hunt.

Without slayers: Houstonians could survive for a good seven centuries on their own. In fact, they’d really only notice that something was up around the six-hundred-year mark, when the vampires finally started to outnumber humans and there were suddenly a lot more parking spaces.

With slayers: Even starting out with just one vampire slayer who recruits a small number of hunters every year, and all of them pursuing vampire killing as more hobby than full-time job, Houston could wipe out all the bloodsuckers and reclaim their city in just 39.8 years. So they should probably get practicing. Finally, a use for the Astrodome!

### Austin, population 1.016 million

We used the “Rice Model” on Austin, which takes novelist Anne Rice’s view of vampirism as a sort of elitist club full of slightly bohemian, self-satisfied bloodsuckers who welcome new members reluctantly, at a rate of about 10 percent. The scenario attributes this to the idea that Rice’s vampires “need victims’ permission” before offering them their own blood to drink, a practice that we think Austinites would embrace. Also, Austin vampires wouldn’t want just anyone, especially if the proposed victim moved here after, like, 1995.

Without slayers: Austinites would survive about 63.6 decades like this, when the vampire population and cost of living would finally destroy them and/or drive them to Round Rock.

With slayers: Given Austin’s love of clubs, we assumed that about 50 would-be slayers would hear about it on Reddit and join the nascent vampire hunter intramural league. Recruitment would then double every year, with all the members devoting their entire lives to it—and probably being really annoying about it. Under this scenario, Austin could be rid of vampires in just 3.6 years! Unfortunately, vampire-hunting would no longer be cool in just under two years.

### Amarillo, population 199,826

For Amarillo, we went with the “Harris-Meyer Model,” which mimics Charlaine Harris’s The Southern Vampire Mysteries/True Blood novels and Stephenie Meyer’s Twilight. This is a world where vampires and humans can peacefully coexist, occasionally engaging in torrid, poignant interspecies romance. We based this link largely on the fact that Bob Dylan once referred to Amarillo as “the land of the living dead,” and also that time a bunch of Amarillo cattlemen sued Oprah Winfrey, which indirectly introduced us to America’s most famous vampire, Dr. Phil.

Without slayers: Because vampires in this world so rarely turn humans, believing it to be a real emotional hassle, their numbers would increase relatively slowly, only killing off the last human after 12.4 centuries. Presumably they would spend about 1,000 years of that span trying to “work out their issues,” before finally just deciding to eat them.

With slayers: Amarillo notoriously loves its local businesses, so there’d probably be a lot of interest in a cute new vampire-slaying boutique. Even if it started small, with just 10 slayers recruiting at a slow speed of 1 percent per year, Amarillo could eradicate all vampires within just 50.6 decades, depending on how difficult it is to obtain a hunting lease.

### Dallas, population 1.341 million

“Damped Oscillation” is the most sensible model the calculator offers, assuming that vampires are smart enough to not drain their entire food supply and hold off on killing too many humans at a time. This way, the status quo can just go on, ostensibly forever. That sounds like a good fit for Dallas, a pragmatic city filled with people who all just sort of ended up there because of work.

Without slayers: The original scenario assumes that slayers are both active and passionately recruiting, but for the sake of argument, let’s say all the slayers finally got fed up and moved to the suburbs. In this case, it would take about 17.5 centuries before vampires overtook humans, although the vampires would keep about 4 million of them alive indefinitely. And, of course, becoming a walking blood-pantry doesn’t mean the humans would ever leave Dallas. Come on. That’s where their office is.

With slayers: We gave Dallas 200 slayers and made it their life’s work to wipe out all the vampires, and apparently it would still take them around 47.8 years to get it done. [Insert joke about it being overseen by TxDOT here.]

### Waco, population 136,436

In probably the most fantastical model, the “Dusk Of Humanity” scenario imagines “500 ruthless vampires” descending on a developing city, not unlike what Chip and Joanna Gaines did to Waco. The do-or-die moment for the town, with vampires subbed in for cupcake shops, spurs its residents to form a slayer task force of 101 strong. The question then is whether it’s too late, or if, ultimately, the influx of vampire-related tourism is worth it.

Without slayers: Ignoring for the moment the model’s recommendation, a slayer-free Waco would have about 14.4 decades before fully succumbing to vampires. In the meantime, they’d only have about 27 years before the vampires outnumber them—and far fewer before they’d begin to outspend them.

With slayers: Now let’s bring those 101 slayers back into the fold, which would see Waco completely vampire-free in just 60.6 years! Of course, it might take another sixty to get rid of all the shiplap.

You can use the Vampire Apocalypse Calculator to find out how your own city would fare against an invasion of the undead. Then go out among the Halloween revelers, and spread the spooky joy of statistical prediction.