Warning! Spoilers for Mortal Kombt below.
Mortal Kombat's iconic villain Sub-Zero is an ancient warrior with ice powers who has survived for hundreds of years. But just how old is he really? It's difficult to say, seeing as how he has such a convoluted history and one firmly rooted in the supernatural. In the movie, he doesn't appear to have aged. But he had lived for hundreds of years. Still, there are ways to narrow it down.
The 2021 movie adaptation of the video game first introduced Sub-Zero hundreds of years prior in Asia, when he was still known as the human, Bi-Han, from the Lin Kuei clan. His greatest enemy on earth and rival was Hanzo Hasashi of the Shirai Ryu clan. Eventually, Bi-Han ambushes Hanzo's family when Hanzo is away and slaughters them, prompting him and Hanzo to battle it out in a duel to the death. Bi-Han is wounded, but he ultimately kills Hanzo (who was reborn as Scorpion). Centuries later, he reemerges as the inhumanly gifted Sub-Zero.
Mortal Kombat never actually confirms Sub-Zero's age, but it's fairly easy for the audience to deduce a general age range. Thanks to the film's opening scene, it's indicated the flashback sequence is set in the 17th century – 1617 Japan, to be exact. From that, audiences can deduce Sub-Zero is at least 400 years old. He appears to be in his late 30s or early 40s when he first appears in the film, meaning he's between roughly 435-450 years old once it jumps to the modern day. As he is the deadliest Outworld opponent in all of Mortal Kombat, it's safe to assume he's used his incredibly advanced age to his benefit.
Sub-Zero's extended lifespan may have even started well before his introduction in Mortal Kombat, however, meaning he could even be much older than it appears. Simply not much is known about his exact origins or what his early life was like prior to his feud with Scorpion and subsequent resurrection as Sub-Zero. This generally vague age range is accurate to the original series of video games. Some version of Sub-Zero has appeared in every one of the Mortal Kombat video games to date but has always remained a rather mysterious figure. Over the years, fans have been able to piece together bits of information about the character's backstory. Fans on a Mortal Kombat subreddit, for example, estimate the video game character's age to be somewhere between 30-50 as a human.
Ultimately, Sub-Zero's age is irrelevant as the mystical warrior has found ways to cheat death over the years, being resurrected multiple times, the first time as Sub-Zero, then as Noob Saibot. The 2021 movie ends with protagonist Cole and his fellow Earth champions killing Sub-Zero. However, pending the ultimate success of the movie, Sub-Zero actor Joe Taslim revealed that he signed a five-movie contract. As death is never really the end for characters in the original video games, this means that fans can likely expect Sub-Zero to return in a potential Mortal Kombat 2. When he inevitably returns, he will likely remain the same age that he has always looked since the opening scene of Mortal Kombat.