Exact Time to Failure

"T-Rex: Whenever there's trouble, their computer is always all "15 seconds until fatal radiation exposure", as though if you get 14, you're fine, and if you get 16, you're dead for sure! Expiry dates, like those on ST:TNG, are false and needlessly strict. God: MAN T-REX YOU'RE ABOUT THREE SECONDS AWAY FROM FATAL RADIATION EXPOSURE YOURSELF T-Rex: It's different when YOU do it! Sheesh! Also what?"

- Dinosaur Comics, Episode 554

Whenever a technological device is about to fail, the Magical Computer knows exactly how long it will take to fail and displays a timer counting down (often with the use of a Viewer-Friendly Interface). Very useful to create a suspenseful situation, in a similar manner to a Time Bomb.

Naturally, there will be no lasting consequences if the failure is stopped in time, even if there's just a millisecond left. Sometimes, the timer is polite enough to wait for the dramatic scene to finish, in which case it's a Magic Countdown. In Video Games, these are very handy for setting up Timed Missions. Related to Ludicrous Precision. See also Race Against the Clock.

Justified in the case of an actual Time Bomb, since defusing it half a second before it would've exploded has the same result as defusing it 5 hours earlier. In just about any other case? Not so much.

Anime & Manga

 * Eureka Seven: the antibody coralians can only remain alive for 1246 seconds (20 minutes 46 seconds).
 * Last Exile: When the Guild first attacks the Silvana, it's stated they can operate for 20 minutes at full power. After exactly twenty minutes, they all break off and leave (including Dio and Luciola, who entered the battle later on). Fridge Logic ensues because they were thrashing the Silvana—since they still had enough fuel to fly back home, they couldn't have stayed the few extra minutes to finish? Or refueled and headed back out?
 * A similar virus attack in Neon Genesis Evangelion.
 * Said virus attack triggered the base's self-destruct mechanism, which is what the countdown was, thus making it an actual Time Bomb and not really an example of this trope.
 * Actually, the virus/angel was hacking into the three magi supercomputers, which must unanimously agree in order to activate the self-destruct. Since the battle is going on in clock-cycles, it's relatively easy for the techs to predict how long (plus or minus a few nanoseconds) before the last of the magi gets taken over.
 * The huge countdown display for EVA-01's auxiliary power batteries that plastered itself all over every screen in NERV during Episode 3. Especially considering it reached zero just as the What-Do-You-Mean-It's-Not-Symbolic-of-the-Week sputtered out.
 * On the other hand, the What-Do-You-Mean-It's-Not-Symbolic shield that EVA-00 uses in Episode 6 lasts longer than it needs to.
 * To be fair, Ritsuko said would last AT LEAST 17 seconds, which meant after those 17 seconds pass there was no guarantee that the shield would maintain its structural strength for longer.
 * And the JA's countdown for meltdown
 * The crew of the Uchuu Senkan Yamato always knew the exact number of days remaining before the extinction of humanity from gradually increasing radiation levels beneath the surface.
 * The English version would always change those dates around. To make one up, the narrator would say "There are only 118 days left!" but the (Japanese) text on the bottom would have a number like 134 which was the number of days left originally.
 * The English version ("Star Blazers") theme song took it further, claiming that if they weren't back with the CosmoDNA in one year, "mother Earth will disappear." Not "life on Earth will disappear," which would have scanned just fine and would have been a little more plausible, but apparently the planet itself. Naturally they got back at the last moment and there was no mention of the slightest damage or harm beyond what we'd seen at the beginning of the series.
 * Planet Namek during the Frieza Saga of Dragonball Z; the planet was about to be destroyed, with "five minutes" mentioned at least once, for ten episodes. Indeed, one episode had "two minutes" mentioned at the beginning, and "one minute" mentioned at the end.
 * Subverted in My-HiME: the time until Artemis the Kill Sat is ready to fire is announced, then it gets prepared earlier than expected, catching the protagonists (and the viewers) off guard. It is explained that "just because it's a satellite doesn't mean it moves at a constant rate".
 * In later episodes of Magical Girl Lyrical Nanoha StrikerS, the exact time for the Cradle to orbit Mid-Childa is shown at the end of the episode. A bit of a plot point considering that the Dimensional Fleet will be six minutes too late unless the Cradle's ascension is somehow slowed...
 * In Saint Seiya, some manner of contrived Heroic Sacrifice (or enemy deathtrap) will kill Saori Kido, reincarnation of the Goddess Athena, When the Clock Strikes Twelve. And it's always exactly twelve hours. To the second.
 * In Naruto Shippuden, in the battle between Sakura and Sasori, Sakura takes an antidote that blocks Sasori's poison-based attacks for exactly three minutes, Sakura can tell exactly how much time has gone by, she even counts down the final seconds before the antidote wears off
 * In Sky Girls, each pilot's nanoskin gel—which shields the girls' skin from extreme conditions—expires in exactly twenty-one minutes and thirty-two seconds. After the gel expires, operating the Sonic Diver is equivalent to suicide: nothing protects their bodies when flying at hundreds of kilometres per hour at high altitude.
 * Subverted in the Read or Die OVA, where, even though the hero's stop the launch countdown with one second to spare, the Ijun launch anyways. In fact, the countdown ending display even ticks from 0 to -1 just to illustrate the point.
 * In Summer Wars, this is a double subversion with the counter stopping with 15 minutes left, only to continue again to stop at a dramatic three seconds.
 * In the last couple of episodes of Science Ninja Team Gatchaman, Leader X attempts to destroy Earth by dropping nuclear bombs into the mantle. The result is supposed to be equivalent to a black hole. Suffice it to say that every bomb EXCEPT ONE drops into the mantle—and because the last one doesn't drop, the reaction doesn't come off.
 * In the second Digimon Adventure movie, Our War Game (and the second part of Digimon The Movie), Diablomon has launched a nuke at Japan from the United States and a five-minute countdown starts up, letting the Chosen Children know that they only have that long before they're wiped off the map. When Omegamon stabs Diablomon in the head, he stops the countdown with one second remaining and the nuke flops harmlessly into the water.
 * Played realistically in Planetes: when a ship is going to crash into a lunar colony, the countdown isn't until the collision, it's to when it will be too late to stop it. By that point, the ship is still a very good distance away.

Comics

 * In a biological variant, Aquaman (and all other Atlanteans in The DCU) originally could survive exactly one hour out of water; after that point they fell down dead. This has been quietly done away with in recent years.
 * The belief still lasts, which allowed Aquaman, in one of his annuals, to put one over on the bad guys.
 * In another biological variant, a Golden Age Batman story featured Hugo Strange. Strange had invented a serum that turned a normal person into a giant Monster Man, strong enough to rip out a support for an elevated train, . Strange injected Batman with this serum, saying it takes 18 hours to work.
 * Hourman's drug-based powers would wear off in exactly an hour, regardless of his metabolism at the time he took the drug or thereafter.
 * One issue of Global Frequency involved a decapitated head, a psychic, and a yelling superior informing the psychic that the person who the head had been attached to had died two minutes ago, and she knew that brain waves last for only a few minutes after death.
 * It used to be the case that a Green Lantern ring needed recharging every twenty-four hours. Nowadays it needs recharging based on how much it's been used.

Films
"Jay: A galactic standard week? How the hell long is that? Kay: One hour. Jay: One hour? Then what? [Incoming message: Deliver the Galaxy or Earth will be destroyed. Sorry.] Jay: Aw, that's bullshit. (cue clock)"
 * In Aliens, Ripley searches for Newt inside the colony's atmospheric processing reactor while a computerized voice gives a minute-by-minute countdown as the reactor ticks its way towards becoming a "cloud of vapor the size of Nebraska." Probably justified in that the reactor's control systems, having real-time information on the temperature, pressure, etc. would be able to predict quite accurately the point at which it would go critical.
 * Also used in the first movie, where a very precise time period is given for both the failure of the cooling system and the (spectacular) explosion of the Nostromo. When Ripley attempts to turn the cooling system back on and literally misses the countdown by seconds, she's unable to do so, likely because Mother (the computer) doesn't like anyone messing with her schedule.
 * Except for itself. Mother's two 30 second countdowns take 36 and 37 seconds respectively.
 * When Johnny 5 is worked over by the goons in Short Circuit 2, a countdown timer on his control panel shows how much time he has left before his ruptured battery drains and shuts him down. As can be expected, he stops the baddies in time and is repaired with only a few seconds of "life" remaining.
 * Dr. Strangelove gives us an aversion that shows why this trope is silly. A B-52 is hit by a missile and begins to leak fuel. One of the crew members works out the loss rate and predicts that they will have just enough to make it to the target and get to ditch by a weather ship. Then, in mid-flight, the fuel loss rate increases and they have to change target. Kudos, Kubrick.
 * Of course this is necessary to the plot: the plane's change of course means that the Russian fighters tracking it to its original target won't be able to intercept it (it's flying so low it can't be tracked by radar).
 * Also, when the Doomsday Machine is activated, they mention that they have enough time to flee to a deep mine shaft, and make the necessary modifications to make it inhabitable, rather than saying something like "If we don't get underground in 72 hours, we're doomed!" Fitting, since a full nuclear winter wouldn't cover the entire earth in lethal radiation for a while after detonation.
 * In Escape from New York, Snake is injected with microscopic explosives that will blow open his carotid arteries in 24 hours—to the second. However, this can be justified if microprocessors are used to time them.
 * In the sequel, Escape From L.A., however, he is infected with the man-made Plutoxin 7 virus, which seems rather unlikely to be something that can be timed with any exactness. Later,.
 * Darkman's synthetic skin, when exposed to light, decays in exactly 99 minutes.
 * In Flash Gordon the countdown is stopped mere seconds before the Moon crashes into the Earth!
 * Parodied in Men in Black.

"Flint: ...and rendezvous here, at the western blowhole in... how long before the world is destroyed? Sam: About twenty minutes. Flint: Just before then!"
 * Averted rather than parodied, it's another race threatening earth, rather than a machine about to blow up.
 * In 2012, the computers installed on the arcs are somehow capable of calculating the exact second the tsunamis will strike the ships, despite the very limited predictability we in reality have of them.
 * Justified, in that this movie takes place in the future.!
 * Subverted in Monsters vs. Aliens. "3... 2... 1... (pause, nothing happens) Maybe my count was wBOOM"
 * In a variant using location rather than time, an on-screen graphic in Asteroid shows the calculated probability that a fragment of Eros will strike particular areas of Texas. The potential zones of impact form an implausibly-tidy pattern of concentric rings, and the fragment strikes dead center, even though the characters had admitted it was only a rough estimate.
 * This is the same movie where they decide to shoot the asteroid with fighter-mounted lasers aimed manually at a fast-moving object ridiculously far away. It works somehow.
 * Parodied in Cloudy with a Chance of Meatballs, with Flint outlining their plan of attack, ending with:

"HAL: I've just picked up a fault in the AE35 unit. It's going to go 100% failure in 72 hours."
 * B.E.N. calculates this trope during the escape from Treasure Planet. They avoid failure by seconds.
 * In Danger: Diabolik, the protagonist takes a capsule that puts him in a death-like trance for 12 hours, allowing him to escape capture. As he wakes, he tells the coroner (who literally had the scalpel pressed to Diabolik's forehead) that if the antidote isn't administered within 12 hours the fake death becomes real. Then his Dark Mistress (disguised as a nurse) reveals that he was out for 11 hours and 57 minutes.
 * In 2001: A Space Odyssey:


 * Of course, this is a subverted trope, as.
 * Parodied in Galaxy Quest, which of course was parody of a Star Trek type series, when they think they've stopped the countdown with several seconds to spare but it keeps on going. It finally stops at 1, and they remember that it always stopped at 1 in the actual series.

Literature

 * In Dan Brown's Angels & Demons (predecessor to The Da Vinci Code), the plot revolves around the search for a bit of antimatter contained in a magnetic bottle powered by a battery that will last exactly 24 hours, complete with a countdown timer displaying the time left to the second.
 * Made slightly better in the film, where the countdown is replaced by a fairly realistic charge bar, not unlike one found on a cell phone.
 * Exploited as the entire point of the story The Cold Equations by Tom Godwin. A small ship is launched towards a planet, carrying a lifesaving vaccine and just enough fuel for the computed weight of the ship, its pilot, food, air, and cargo for cost reasons. A young girl stows away on the ship to go see her brother, who happens to be on the planet the ship's heading to. Problem is, her mass wasn't figured into the calculations of the fuel needed—so her very presence on the ship has doomed it to crash when it runs out of fuel and has no way to slow down once it reaches destination and the fuel runs out early.
 * Fully justified in this case, since such calculations are relatively straightforward (and in fact done by organizations such as NASA all the time).
 * Lampshaded in the third part of John Ringo's Ghost when the French bomb squad team, after several hours of stressful drilling, finally manages to bore to the detonator device, which has a digital countdown display. The guy doing the drilling freaks out when he sees it (it only has about a minute or so left) and later decides that it was put there to mess with whoever was unlucky enough to have to drill into the bomb.
 * The poem "The Deacon's Masterpiece" (a.k.a. "The Wonderful One-Hoss Shay") by Oliver Wendell Holmes describes a one-hoss shay built to have its weakest part just as strong as the rest. The contraption lasts for a hundred years, and then disintegrates all at once. (Randall Garrett had a homage to this with the "Von Horst-Shea" process in one of the Lord Darcy stories.)
 * Justified in Dune by Frank Herbert. The Big Bad knows exactly when the Action Mom will wake up from the sleep drug she was given. When he tells her this, she immediately realizes that he must have had access to secret and detailed medical information about her.
 * Subverted in Showdown At Centerpoint, the third book of Roger McBride Allen's Corellian Trilogy, set in the Star Wars Expanded Universe. Han and a couple Allies of the Week are falling towards a planet's surface on a ship (which is battle-damaged, and even at its best made the Millennium Falcon look cutting-edge and ultra-strong) with a none-too-reliable altimeter. When they reach three hundred meters, Han wonders how accurate it is. When they hit neg ten, he decides "not all that accurate." They finally hit the ground at about negative fifty meters.
 * Later, the cavalry's ship's computer was counting down how long their Phlebotinum-aided hyperdrive could continue functioning in a hyperspace-negation field. The timer hit zero, but the ships remained in hyperspace, prompting the technician in charge of the Phlebotinum-drive to point out, a little ruefully, "it was just a guess."
 * In the Animorphs series, there is supposedly a hard two hour time limit on remaining in morph. It's a good thing Ax can keep perfect time in his head because they invariable demorph with seconds to go. Usually with comments about how hard it was to demorph that time or how they almost ran out of time.
 * It does vary, since it's occasionally mentioned that the two hours can vary by as much as several minutes (though it coincidentally is never less than 6 seconds from the two hour mark when a morpher's up against the deadline).
 * In one book they are able to demorph (with great difficulty) even when they appear to be seven minutes over the time limit. Though Tobias does wonder if the clock was just set to the wrong time.
 * "Self-destruct sequence activated. T-minus-15 minutes to self-destruct. Thank you and have a nice day!"
 * It's even stranger when you take into account that Ax constantly refers to them as "two of your hours," implying that Andalites have a different system of keeping time. This just raises even more questions as to why the time limit would be easily measurable in (what is, to them) an alien time measurement system.
 * Also, Yeerks have to feed on kadrona rays every three days, or they die. It's suggested though, that it might not necessarily be exactly 72 hours, but just somewhere around that time limit. When Jake is infested, and the yeerk in his head is starving, the yeerk becomes delerious for the last few hours of his life, and Jake is along for the ride, so it's hard to judge exactly how much time has passed.
 * It's also possible, when Kandrona starvation is being used as a particularly sadistic method of execution, to extend the process. Apparently Visser Three can make a Kandrona starvation last weeks.
 * In Nevil Shute's novel No Highway, Theodore Honey has determined, almost down to the hour, how long the Reindeer airliner will last before the tailplane experiences metal fatigue and breaks, dooming the aircraft.
 * Averted in Joe Haldeman's The Forever War, all failure times are given in half-lives (ie, after said period there's a 50% chance it hasn't blown up yet).

Live Action TV
""Shockwave impact in three, two, one. *pause* More or less.""
 * Star Trek does this one all the time.
 * Happens constantly with the Vulcans. Made more logical when they made an android a crewmember in Star Trek: The Next Generation.
 * Star Trek: Voyager played with this when Janeway decided to take a bunch of her worst crewmembers out on a mission to get them to shape up. One of them, a woman who can't do 24th century math to save her life, gets put in charge of the one thing you need math for: calculating time to impact.


 * The quote from Dinosaur Comics at the top of this page refers to an episode of Star Trek: The Next Generation. The ship is being subjected to severe radiation. The computer reports the exact time, down to the second, when the accumulated dosage will become lethal. The implication is that this time is meant to be uniform for all crew members. But even if it were, say, the time when radiation would be lethal to the lowest common denominator (the Littlest Cancer Patient, for example), it's still a long stretch to believe that any time before that, the damage would be perfectly fine to recover from, but the instant you hit that deadline, it becomes lethal with no hope of recovery. And presumably any damage before that point could be cured with a complete recovery, otherwise Dr. Crusher et al would be working a lot faster before those radiation burns, mutations, and sterility become downright miserable.
 * The majority of the ship's crew appears to be human, and it's quite possible that most other species have near-human fatal exposure levels. There will also likely be an acute (short time/instantaneous) exposure level beyond which even 24th century medicine is unable to stave off imminent death.
 * The Cylon virus attack in the new Battlestar Galactica Reimagined. A second-season episode involving the virus was partially subverted when Lt. Gaeta, in charge of watching to make sure the virus doesn't make it through the network firewalls he installed, ducks under the table to disconnect the network, and fails to notice that the VIRUS INFILTRATED THE SYSTEM.
 * This one is particularly stupid because if your computer knows enough about the virus and its activities to know how far along it is in compromising the computer's systems, it should be able to freaking fraking stop the virus!
 * Far more ridiculous is the fact that connecting some computers together in a closed, wired network immediately makes them vulnerable to attack by the Cylons.
 * The virus was already in one of the computers. Wiring them together just allowed it to spread to critical systems.
 * Mocked in Stargate Atlantis episode "Progeny", wherein Sheppard demands to know how long Rodney's interference will keep the Replicators at bay. Rodney has no idea, and, without trying to hide it, just makes up an answer—and is yelled at when they reactivate early.
 * A Running Gag on Atlantis is for Sheppard to ask Rodney or the team doctor for Exact Time to Failure or success, despite the latter's protests that often such things can't be predicted or that they just plain don't know.
 * And yet, in "Critical Mass", McKay gives a ballpark of estimate of "we maybe have half an hour", but subsequently gives exact timings, finishing with the Just in Time ending.
 * And its parent show, Stargate SG-1, played around with it a couple times. The gate itself has a 38 minutes limit for how long it can stay open, and whenever it stays on for longer, it's because of outside interference and usually means that the base is screwed. On one occasion, this time limit is counted down to, and passes, with the gate staying online. As the characters start talking about how they have to alert the proper people that the world's about to end, the gate shuts down on its own.
 * There's an episode where Teal'c is basically trapped in the gate before he could come through, and if it gets reactivated again, he'll die. This trope is averted at first when Carter's given a 48-hour deadline to find a solution, explicitly because the whole Stargate program can't be shut down indefinitely for the sake of one man. Then it's played straight when she learns the Air Force got the "48 hour" idea from Dr. McKay, who told them that Teal'c would be dead by then anyway. Then it's subverted when it turns out he was just making a ballpark estimate and didn't really know for sure. This contributor suspects the writers were deliberately taking a jab at this trope with the whole episode.
 * ... and then they played it completely straight again in the Atlantis episode "38 minutes" - a small shuttle gets mechanically jammed inside a gate in outer space, so when the event horizon opens it is cut in half. Everything's under control for the 38 minutes the gate stays open, but after that time there might have been half a shuttle floating in space.
 * Lost, besides featuring a prominently displayed countdown for much of the second series, contains a rare non-technological example of this trope: in an episode of the third series, Jack, performing surgery on Ben, intentionally makes a small incision in his kidney and announces that if he doesn't sew it back up in an hour, he'll die. This is shown to mean that he will die in precisely 60 minutes and no earlier, and the other characters repeatedly make reference to how long is left on the "countdown"; in reality, a person in such a condition might die at any time within the hour, or might live longer, but an exact estimation like that would be impossible to make.
 * Being that he's only there because he's a spinal surgeon, the other Others have no damned idea if he's spewing bullshit or not.
 * The fourth season episode "The Other Woman" also features a computer which knows, to the second, how long one can mess with lethal gases before contamination occurs.
 * In an episode of CSI, while trying to locate a person buried alive, the team calculates how much power is in the battery that's being used to vent him oxygen. One of them then starts a watch timer, and despite the obviously rounded figure (also the fact that they have only a vague idea of when he was actually buried), the oxygen flow is cut off within seconds of the timer running out.
 * And of course, they fail to take into account that, in such situations, it's not lack of oxygen that kills you, but buildup of carbon dioxide...
 * Subverted in an episode of the educational series Read All About It: a Cliff Hanger shows our heroes trapped on a doomed planet as the countdown to its destruction reaches zero. In the next episode, the planet remains intact for several more minutes as the countdown was "only an estimate."
 * Occurs in the Mash episode "Life Time", wherein a wounded soldier is said to have only twenty minutes before damage to his aorta and a consequent lack of blood flow will cause permanent brain damage and/or paralysis. The episode unfolds in Real Time, complete with a ticking clock icon in the corner of the screen. Subverted slightly in that the staff decides to immerse him in ice to buy more time. Therefore, the deadline is slightly missed but the patient wakes up seemingly unharmed, although he may have still have had damage that wasn't immediately evident.
 * In the MacGyver episode "Nightmares", an interrogator gives MacGyver a slow-acting poison, and tells him that if he doesn't get the antidote within six hours, his death will be inevitable. There is a prominently-displayed countdown timer. MacGyver gets the antidote with two and a half minutes to spare, and makes a full recovery. It's never explained how they were able to state the time limit so exactly—the interrogator says that the poison was calibrated specially for MacGyver, but that just changes the question to how they got the medical information about MacGyver they'd need for the calibration.
 * Played with in one episode of Monk, the title character is buried alive in a coffin. Upon learning this, Stottlemeyer says that there are 44 minutes of air in a coffin...unless the occupant panics. There's a brief pause, then everyone starts rushing.
 * Made even worse by Monk refusing to put out his candle, despite it eating up the oxygen.
 * Even worse is an episode where we're supposed to buy that there's an exact countdown to the point where a crucial piece of evidence in someone's stomach will be too digested to be of any use. They get it out with literally one second to spare, and apparently it's perfectly fine.
 * The Doctor Who episode "Journey's End" had the current companion, Donna, and the TARDIS itself, tossed into a big vat of TARDIS-eating energy. Much things exploded, there was lots of anguish and then one second before it was supposed to be destroyed, Donna and Plot save the day. All the observers think the TARDIS was destroyed on schedule.
 * The episode "42" revolves around a countdown of, er, 42 minutes until a spaceship crashes into the sun.
 * "Time Crash" has "Two minutes to Belgium!"
 * The 2010 Christmas Special has a
 * In "Let's Kill Hitler" the doctor is poisoned and will die in thirty-two minutes.
 * On 24, people make exact time estimates ("It'll take me 13 minutes to get to the airport!") a lot, due to the Race Against the Clock nature of the show.
 * In one episode of Bones, a serial killer demanded ransom, giving a time limit of twenty-four hours, I believe. The kidnappees were buried alive with exactly that much air available. Subverted in that
 * Justified several times in House, when a risky procedure (such as stopping a patient's heart) is allowed to go on for a very specific time, watched carefully by the team. Subverted in that, when they run out of time, House invariably argues that the time limit is a rough guideline and they should keep going. Of course, the patient almost always makes a full recovery either way.
 * The Animorphs example is worse in the TV show. In the books, morphing is possible but extremely difficult as you near the limit, and there are times when they could've been a few minutes over the oft-repeated two hour mark. In the show, however, there's an instance of Ax (of the perfect timekeeping sense) counting down his morph time limit to the second. He demorphs at the last second as easily as anyone with plenty of time left, with the implication that one second later, it would have been completely impossible to demorph at all.
 * Garo: Makai Knights have 99.9 seconds of enhanced armor time

Video Games
"Announcer: Reactor explosion timer destroyed. Reactor Explosion Uncertainty Emergency Preemption Protocol initiated. This facility will self-destruct in two minutes."
 * Aside from the end-of-game self-destruct runs, the Metroid series has done this more than once. One example: in Metroid Fusion, the space station's computers predict that the overloading core will melt down in six minutes. Since it's a Timed Mission, you have precisely six minutes before it does just that.
 * In Final Fantasy VI, everyone's favorite purple octopus Ultros is trying to drop a four-ton weight on a character (bear with me). He says "N'ghaaa! This is heavier than I thought! It'll take me five minutes to drop it!" Yes, this means that you have exactly five minutes to stop him.
 * Then there's the Disc One Final Dungeon, The Floating Continent. Six minutes, two irritating bosses and the urge to try to collect all the treasures scattered throughout the exit route. And then there's the wait for Shadow...
 * The Resident Evil franchise features several timed sequences due to Self Destruct Mechanisms, which conveniently include boss fights. Yes, the timer ticks down while you're fighting the boss. Yes, if it goes to zero, you die go all the way back to a save point before the countdown, at least.
 * The Chronicles of Riddick: Escape From Butcher Bay has a level where you're trapped in the sewers with a shotgun with a built-in flashlight. Only problem is, the flashlight was damaged and is now flickering, and a computerized voice (in the shotgun, remember) helpfully informs you that it will break entirely in six minutes.
 * Kingdom Hearts II's Timed Missions really had no reason to play this trope to a T, especially seeing as the moment time runs out the screen simply fades to black and no actual "death scene" is given. This becomes especially ridiculous when you have to fight Demyx's water clones, which like cause nuclear meltdown or something or other when time runs out.
 * Most. Annoying. Fight. EVER.
 * Sonic Adventure 2 did this with its timed missions as well. The fading to black thing.
 * Done as part of a cinema in Final Fantasy VII. When Cid grapples with the decision to blast off in a rocket, incinerating a woman, Shera, who stayed behind to fix the oxygen tanks, a timer, normally reserved for gameplay purposes, pops up and counts down as dialogue rolls. Cid hits the button to abort at the last second. This ends up subverting the trope somewhat since, even though Shera was spared, cutting the engines damaged the rocket and caused the space program to lose all credibility, making it several years before another attempt into space is made. Before then, a town formed around the damaged rocket which Cid and Shera took residence in.
 * And, in a later gameplay sequence, it's played straight with.
 * Another gameplay sequence involves trying to stop a train from crashing into a settlement. Normally this would be a subversion, since the train moves with constant speed, but even when you start fiddling with the controls and changing the train's speed, the timer is not affected.
 * Final Fantasy VII loved this trope and has timed escapes pop up every so often. You're even subjected to one shortly after starting a new game!
 * Done oddly in Advance Wars: Dual Strike. Even though the turns progress in days, some missions have a timer that operates in real time. So even if it takes twelve "days" to complete the mission, the fifteen-minute timer could only have advanced by a single minute. This is compounded by the fact that the characters discuss the timer and stress how time is of the essence. It's better not to think about it.
 * Done straight in Advance Wars 2 where on the missions to capture enemy laboratory before they destroy their weapons data, you are given a specific amount of days to invade before the data is destroyed. I always found it odd that getting there on the final day didn't result in getting a large amount of half deleted plans...
 * Subverted in Metal Gear Solid 2: You are given a 10 minute time limit before the commander of the base you're infiltrating finishes his speech and all the marines go on duty. If you wait till the time limit runs out, it turns out he's running long so you get some extra time.
 * If you actually listen to his speech, you'll quickly notice that he has a tendency to go off-speech (even though you don't have the text of the speech available, his tangents are pretty obvious), justifying the longer-than-expected speech. There also isn't a timer in the mission: when he's done with his speech, you fail, but you don't know when that will be!
 * In Fallout 2, you can wind up contaminating the Sierra Army Depot by removing one of the virus samples from storage, which will promptly break. You then have a few minutes to leave before the base is fully contaminated. Even if you loiter around in the very room you broke the sample in, you'll be perfectly fine as long as long as the timer doesn't run out completely. Fail to leave, or leave in time and then walk back, and your character will melt. (I.e. the 'killed by plasma' death animation.)
 * Assassin's Creed II has a few timed side-missions which give you a countdown timer for you to complete the task. While this is understandable for the racing minigame (this is the time set by the previous racer, try to beat it), some of the other missions are predicated on a guard running away after exactly one minute of combat.
 * Just for the record, that mission involves Ezio having to carve his way through ten Brute guards...in one minute. That's six seconds per guard...and they don't die easily unless you poison about half of them first.
 * The Space Quest series features a couple of these timers.
 * In the first game, you set the Star Generator to explode. Justified as the Star Generator detonation sequence is exactly five minutes long by design.
 * In the second game, after killing Vohaul, he sets his asteroid base on a decaying orbit. Failure to leave before time is up means you die with the base. Somewhat inverted in that, although the Time To Failure is always the same (ten minutes, give or take a few seconds), you never actually see it. It's also plenty of time to escape, even if you take the long way to doing it.
 * In the third game, you have a set amount of time to escape the volcanic planet Ortega after setting off a chain reaction explosion. The timer is once again very generous (ten minutes), but once again, you don't actually see it.
 * In the fourth game, after setting up the evil supercomputer to do a full system format, you have a limited amount of time before the format actually begins. Because formatting the computer without dealing with the virus will not save the day, you have until the formatting begins to, well, save the day. Played with in that you have 5000 "somethings" to deal with the problem. This translates into about six minutes.
 * In the fifth game, you set off the Exact Time To Failure by activating the self-destruct sequence. It's exactly ten minutes, which again is about five minutes more than you need if you're slow.
 * Elder Scrolls Oblivion is mostly a game where you can take years (game time) to get things done but one mission features a fifteen minute countdown before a giant city destroying war machine marches though a portal and splats the new emperor.
 * Descent has a reactor explode countdown.
 * Doubly subverted in that it appears as if you have a few moments of the screen fading to white after the countdown completes to enter the evacuation tunnel, but the effect is unchanged, right down to the tunnel exploding behind you no matter if you make it by one white frame or one whole minute.
 * Used, though played with a bit, in Crisis Zone. After beating the final boss, you manage to stop the nuclear reactor from going critical with seconds to spare. Despite this, the control room still explodes soon after. It's not clear if it's just the control room blowing up due to all the bullets and grenades being tossed around, or the reactor still causing some damage due to how close it was to exploding.
 * Games in the Time Crisis series always have an Exact Time To Failure in every segment. If you fail to kill all the targets and move on from your current spot within 40 seconds, you'll lose a life (presumably from being flanked). If it wasn't your last life, the timer is reset to 40 and you can continue. The intent is obviously to force the player not to abuse the hiding mechanics and be more aggressive.
 * Star Fox 64: Fortuna has a countdown till the bomb in the base goes off. With correct timing you can have Fox go in to defuse the bomb a few seconds after ROB says that the bomb is exploding.
 * In Freespace 2, the last mission has a countdown until a star system is destroyed by a supernova.
 * XCOM Interceptor averts the trope rather spectacularly: any mission in which time is a factor (defending a base, attacking an enemy ship about to go into hyperspace, or, for example), you're given periodic updates as to how close you are to running out of time ("Enemy hyperdrive at 75% charge"), but the time can vary based on a number of factors, most obviously how long it took you to respond to the particular emergency.
 * Le MU from Ever 17 even has audio announcement of last seconds countdown before the whole building will collapse. Which is kinda strange, because earlier was said, that calculations of this time has 6 hours margin of error.
 * Might it be possible that the margin of error shrinks as the time to collapse approaches? In other words, the margin of error itself is a percentage based on the estimate.
 * Averted in the opening of MadWorld. The Big Bad unleashes a deadly virus across the city. He warns the citizens that everyone will be dead in 24 hours and that anyone can get an antidote as long as they kill someone. Seems like a pretty straight example of the trope so far, but then a member of the crowd collapses bleeding. The Big Bad then suggests they hurry up as the virus' incubation time varries from person to person.
 * StarCraft has a few missions in the brood war campaign where a character manages to estimate the exact amount of time until an important event will happen. These estimates are used as setups for timed missions.
 * The Subspace Emissary story mode in Brawl has a boss fight with Meta-Ridley while a bunch of characters are escaping a self-destructing ROB factory on Captain Falcon's Blue Falcon. The fight itself gives you two minutes to defeat Ridley before the factory explodes while you're still inside (and subsequently lose the battle).
 * In Nine Hours Nine Persons Nine Doors, the participants of the Nonary Game have 9 hours to escape.
 * Mass Effect has a few of these in both games. Some missions, assignments and tasks must be completed within certain time limits. Otherwise, the ship crashes, or the missiles launch, or the, or the colony explodes, or the , or something else bad happens that will really ruin Shepard's day.
 * Mass Effect 2 does this with the Arrival DLC. Shepard has just over an hour to.
 * Portal uses this in both games. In the first, it's "Exact Time to Death by Neurotoxin". Portal 2 plays with it like you wouldn't believe. The first timer is the same as above. When that fails, it switches to a timer for the reactor meltdown. Then the meltdown timer is blown up, so the facility activates a Self-Destruct Mechanism to remove the uncertainty of not having a timer.

": Let me just flag something up: according to the control panel light up there, the entire building is going to self-destruct in about six minutes. I'm pretty sure it's a problem with the light -- I think the light's on the blink, but just in case it isn't, I am actually going to have to kill you, as discussed earlier. So let's call that three minutes, with a minute break afterwards, which gives me a leisurely two minutes to figure out how to shut down whatever's starting all the fires."
 * It's also given a Lampshade Hanging when you first enter the Final Boss lair.


 * The oxygen timer in Dead Space and Dead Space 2, Isaac will die when it hits zero, even if logically you could stagger on for a few seconds.
 * Justifiably, as the last ten seconds or so, he's already choking for air. Presumably, the timer isn't indicating how long his oxygen supply will last, but rather how long he has until he's unable to continue due to asphyxiation.
 * Golgo 13: Top Secret Episode features "Exact Time to Nuclear Missile Launch" in its final battle. Noteworthy in that you actually lose not at zero, but when the timer hits 0:13.
 * In the last level of Halo, Cortana is able to tell you just how long you have before the reactor you threw explosives in blows up, despite noting that it must have been more damaged than she thought it had been.

Web Comics

 * This comic from Order of the Stick has the magical version of this. Justified because Vaarsuvius is just that intelligent.
 * It also should be pointed out that in Dungeons & Dragons, on which the comic is based, one round is six seconds. This would simply mean that Vaarsuvius knows that the spell will end in two rounds.
 * ... and then spends one round explaining things, so verbosely that it's no longer a free action. The next two rounds are spent disintegrating the dragon (presumably s/he won initiative).
 * The Wizard ALWAYS wins initiative.
 * Lampshaded, naturally, in Adventurers!!; to Karn's obvious surprise, the bomb goes off earlier than expected. The guy who gave him the exact time admits he's not a bomb expert, as well.

Western Animation

 * A particularly absurd version in The Simpsons, where Homer slacks off on his job and then has to race to the power plant's manual override to prevent a meltdown. Mr. Burns is leading excercises outside the plant, which is played up as a countdown to the meltdown, despite having nothing to do with it.
 * Camp Lazlo: In "The Big Cheese", anyone who eats the acidic cheese will disintegrate in exactly 13 minutes.

Real Life

 * With sufficiently powerful computers able to access the right data, a fairly accurate prediction of time of failure is possible, especially when the failure process occurs at a constant or predicatable rate. A good example today is electronic devices which can give a fairly good estimate of remaining battery time, based on the current state of charge and the rate of discharge, although the fact that the discharge is rarely constant affects the accuracy. With the right sensors, the time of failure of a mechanical system should be predictable, based on wear level and rate of wear. In other cases, a failure may occur rapidly at a specific point, for example when a particular load or temperature is reached, and again it can be possible to get a good estimate of failure time based on the rate of increase.
 * It should be noted, however, that such systems tend to update the estimate every now and then, taking into account the most recent rate of progress. For example, if your laptop computer tells you that you have 55 minutes until the battery dies, and you spend the next 20 minutes doing something more energy-intensive than the 55 minute estimate had assumed, then the battery monitoring program might say that you have only 28 minutes remaining.
 * SMART is a system to predict hard drive failure by measuring the rate at which the mechanical components deteriorate.
 * There's an easy-to-remember phrase describing how long a person is likely to survive, if deprived of basic bodily needs: "Three minutes without air, three hours without shelter, three days without water, three weeks without food". While handy, it fails to take into account issues such as activity levels, a body's initial state of oxygenation or hydration, or how large the person's nutrient reserve is when they begin starving.
 * As well as gender, age, weight, amount of body fat, general health, other medical conditions than could be worsened by the deprivations, external conditions (heat, humidity...), etc., etc.
 * "You are moving 30 MB over a 100MB connection. Calculated time remaining 2,457,494 minutes."
 * There's also torrent download timers, where, depending on the number of peers you have, which take time for the computer to locate, estimated download times for a 100 MB item can vary from 2 minutes, 36 seconds, to 4 days, to 5 weeks, to ∞.
 * Expiration dates on items such as food and medicine are estimates of how long they will remain consumable; actual results vary according to factors such as storage conditions. With the exception of infant formula, said food estimates don't even have any regulations for what they're based on.