Original Fallout lead Tim Cain says the team planned for there to be 1000 Vaults, but he thinks there are actually far fewer in the setting

In a new vlog on his YouTube channel, veteran programmer and RPG designer Tim Cain revealed some more of the background he and his team initially planned for Fallout's vaults. The crew at Interplay conceived of there being 1,000 Vault Tec vaults in the United States, a figure with some in-game and real-life logistical issues that Cain then explores, all with the caveat that this is him having some fun: "This is just me talking about it⁠—it's not canon!"

First and foremost, the 1,000 number was just an aesthetic choice: "The only reason this pin was even placed in the original game was when Leonard [Boyarsky, Fallout 1's lead artist] was doing the vault suit, he asked me how many digits he'd need to keep on the back." Cain said. "I thought, well, let's just say there's a round number, there's a thousand.

"I'm a programmer, I start counting at zero, three digits."

The idea of there being a "Vault Zero" then figured into a Fallout lore tidbit Cain previously shared on his YouTube channel: the vault experiment was in preparation for long haul interstellar travel. I first thought of the LA test vault from Fallout 1 as a Vault Zero candidate, but apparently there's an explicit "Vault Zero" in Fallout Tactics.

Cain also casually dropped that another Fallout lore keystone was borne of stylistic concerns: the thirteen "commonwealths" of Fallout's crueler, more brutal America only came after Fallout's artists designed a thirteen-star American flag for the game. "According to Leonard, [the Fallout art team] just did it because it looked cool."

But even with 1,000 vaults in the US, Vault Tec wouldn't have saved that many people, maybe "a third of 1%" of the US population by Cain's reckoning. "If each of these vaults held something like a thousand people, that's only a million people that are going to be saved in Vault Tec vaults, which is way less than the population we imagined."

Also, while artistic license and fudged scale is definitely at play in these games, a thousand people per vault? I think Vault 101 in Fallout 3 had like, a dozen people in it. They all came to my birthday party.

Regardless, Cain doesn't even think that best case scenario of 1,000 vaults is even likely, looking at the density of vaults in the games. With Fallout 1 and 2 showing us the entirety of California, there should theoretically be at least 20 vaults between the two games. "Fallout 1 and 2 combined only had about four to six vaults in them that were clearly defined," Cain said. "And that's if you count the un-numbered ones, like whatever Harold's vault was."

While the TV show adds four more to Cali, that's still only half of the 20 minimum you'd expect for a high-population state, and the other games don't fare much better in terms of vault density. Cain thinks there's a plausible in-universe explanation, though: "The conclusion here is Vault Tec: They didn't build all 1,000 Vaults, they didn't even come close."

"Vault Tec built fewer than half, probably far fewer than the vaults they were supposed to." Cain said, likening the company to the myriad real life government contractors who bid the lowest and then underperform in our vaunted public-private partnerships, a state of affairs that could only be worse in Fallout's pessimistic alternate universe. "I think there are far, far fewer than a thousand," Cain concluded.

Going off the Fallout Wiki, I count 41 vaults shown across the games and TV show⁠—we recently ranked 26 of them from worst to best⁠—subtracting the two on the wiki's list from Fallout: Brotherhood of Steel (I mean, come on), as well as Fallout 3's Museum of Technology display and Mr. House's Securitron Bunker from New Vegas.

A Vault Tec map visible in the show and analyzed by Werthead on Reddit, meanwhile, shows about 120 vaults in the US and Canada, far fewer than Cain's original estimate. So if any of this is binding⁠—and it categorically is not, because it's all fiction⁠—we've still only seen about a third of the vaults in Fallout's setting after 27 years and eight games. I'm still not counting you, Fallout: Brotherhood of Steel.