Some content in this article is derived from information featured in Harry Potter and the Cursed Child, and, as such, spoilers will be present.
A Time-Turner is a special timepiece in which an Hour-Reversal Charm has been encased, for added stability. It is a device used for time travel, and it resembles an hourglass on a necklace. The number of times one turns the hourglass corresponds to the number of hours one travels back in time (although, it should be noted that the longest period that may be relived without the possibility of serious harm to the traveller or to time itself is around five hours).
- "Hermione's immense workload finally seemed to be getting to her. Every night, without fail, Hermione was to be seen in a corner of the common room, several tables spread with books, Arithmancy charts, rune dictionaries, diagrams of Muggles lifting heavy objects, and file upon file of extensive notes; she barely spoke to anybody and snapped when she was interrupted."
- —Hermione's workload due to her Ministry Time-Turner[src]
Hermione Granger received one from Professor McGonagall in 1993, so that she could attend more classes in her third year than time would allow. Since McGonagall made her swear to not tell anyone about it, she did not mention it to Harry Potter or Ron Weasley until the end of the school year, when she and Harry used it to travel back in time and save Sirius Black and Buckbeak from certain death. Special permission from the Ministry of Magic had to be sought to allow Hermione to use one, but her academic record ensured that permission was given.
Hermione found her third year stressful with the extra class load, and therefore decided to drop Divination, which she despised, and Muggle Studies, which she did not find very useful, given that she was a Muggle-born. This allowed her to have a normal schedule once again, and she returned her Time-Turner. Ron was disappointed that Hermione did not tell her friends about it, despite her promise to McGonagall.
The entire stock of Time-Turners, located in the Time Room, in the Ministry of Magic were rendered useless during the Battle of the Department of Mysteries in 1996. While not "destroyed" per se, due to the way one of them fell when their counter was knocked over, the entire stock was trapped in an endless loop of falling over, un-falling, and then re-falling, in an endless cycle for all eternity, and are thus unable to be used. 
In 2020, shortly before the start of Albus Potter's fourth year and Hogwarts School of Witchcraft and Wizardry, Harry Potter, in his capacity as the head of the Department of Magical Law Enforcement, discovered a previously unknown Time-Turner on the person of Theodore Nott. The Time-Turner was said to be not just a simple "hour-reversal turner," but rather a true Time-Turner. The Time-Turner, which allowed one to travel far back into the past but for only five minutes before returning, was kept hidden in the office of Minister for Magic Hermione Granger, but was later stolen by Albus Potter and Scorpius Malfoy, who intended to use it in order to save Cedric Diggory and return him to his dying father. The two then set in motion a disastrous chain of events and alternate realities, though they managed to correct events and set time right.
Both were abducted by Delphini, who until then posed as their friend and incited their goals. Revealing her true intentions, she took possession of the Time-Turner and set off to ensure her father would never lose his power, and destroyed it to ensure she would not be forced to return to the present via the 5 minutes restriction. Following Draco Malfoy's revelation that he possessed a Time-Turner of his own that had been passed down from his father, one that did not possess the five-minute restriction nor five hour safety boundary, and thanks to a message left from Albus in the past for his father to find in the future, Delphini was stopped by the combined might of both generations.
Time-Turners that are issued by the Ministry of Magic have an Hour-Reversal Charm placed onto them. These have a limit of travelling back to a maximum of five-hours, which is the determined safety limit to the person or the fabrics of time. These devices are limited in quantities, and are not easily replaceable, as during the Battle of the Department of Mysteries in which the Ministry's entire stockpile were destroyed, they were not repaired nor replaced. Hogwarts students can apply for such a Time-Turner in order to take more classes, but they must undergo a large amount of screening process and must follow a most stringent set of rules, such as not abusing its powers nor let any outsiders know of it.
There also exists a type of Time-Turner that is not simply an hourglass with an Hour-Reversal Charm placed onto it, but rather a "true" Time-Turner. Such a device allows the user to go back to whatever time in the past they desire, far beyond the five-hours boundary. These devices were created by Saul Croaker, and the prototype fell into the hands of Theodore Nott before the Ministry found it; due to the one he possesses was made of inexpensive metal and was not the finalised version, the user can only stay in the past for five minutes before being sent back to the present, though in this small window can still lead to catastrophic effects, as demonstrated by Albus Potter and Scorpius Malfoy. If the device is destroyed while the user(s) are in the past, then they will not be sent back automatically, but will remain stranded.
Lucius Malfoy purchased a "true" Time-Turner from Croaker, due to his liking of collecting powerful artefacts. The one he possessed was a finalised version, gleams like gold, and unlike the one Nott possessed was not restrained by a five-minutes duration. He passed it down to his son Draco Malfoy. Harry Potter noted that had the Ministry caught wind of Draco holding onto such a dangerous device, he would be sent to Azkaban for it.
Time-related magic is unstable, and serious breaches in the laws of time result in catastrophic events. Possible scenarios include a wizard or witch killing their past or future selves by mistake, or altering one's life path in such a drastic fashion that it can result in temporal anomalies such as un-births. As such, the Ministry of Magic seeks the strictest guarantees if it permits the use of Time-Turners: Time-Turner possession is hedged around with literally hundreds of laws, and the most stringent laws and penalties are in place to prevent their misuse.
The consequences of meddling with time could be as severe as creating an alternate timeline, such as one in which Lord Voldemort was never defeated and still ruled. The person who had used the Time-Turner, however, if still existing, would still have memory of the events of the uncorrupted timeline, but would have to learn secondhand the nature of the changes which had been made.
Behind the scenes
- In the film adaptation of Harry Potter and the Prisoner of Azkaban, while the importance of not being seen while travelling back in time is stressed, Harry and Hermione pass by the Clock Tower Courtyard while following their past selves. However, the executioner was sitting there, sharpening his axe, so he must have seen two pairs of Harrys and Hermiones. Although it could be explained that he was too busy sharpening his axe that he did not notice the second Harry and Hermione coming through.
- In the book, when the Time-Turner is used it takes the person back to the location where they were present at the time they'd gone back to. However, in the film adaptation, when the Time-Turner is used it leaves the person in the same place they were when they turned time back. The GBA video game version has the user appearing at an entirely random place (i.e. Harry and Hermione use it in the Hospital wing and appear at the Forbidden Forest).
- The possibility of time travel within the Harry Potter universe may seem to allow many plot holes, but characters appear to use them for trivial tasks that have no effect on existence as a whole. The one notable use of a Time-Turner within canon, the Rescue of Sirius Black and Buckbeak, obeys the Novikov Self-Consistency Principle. This theory of time-travel, stating that "Nothing can be changed because anything a traveller does merely produces the circumstances they had noted before travelling," is incidentally reminiscent of J. K. Rowling's employment of self-fulfilling prophecy. However, references to catastrophes that can take place when time travelling (a reference to a wizard travelling to the past and being killed by his past self in Prisoner of Azkaban, or Eloise Mintumble's time-travelling mishap in Pottermore in which several people end up un-born in the present) seem to go against Novikov Principle, indeed creating paradoxes. Harry Potter and the Cursed Child also shows that reckless use of a Time-Turner can result in the creation of an alternate timeline.
- Knowing that time-related magic is unstable, there might be different ways to experience time through magic. This would explain catastrophic events as with Eloise Mintumble, and also paradoxes as result of poorly performed time-related spells.
- When Eloise Mintumble time-travelled and changed things, it was noticed by other witches and wizards from the original timeline who went to retrieve her. When Albus Potter and Scorpius Malfoy time-travelled and changed things, no one from the original timeline knew they could retrieve them. They never mention being able to retrieve them in the same way Eloise was retrieved. It may be a continuity error or they use a different kind of Time-Turners.
- It is unknown what the effect of excessive Time-Turner use might produce. The user might still age while within an hour produced by the Time-Turner, and if so, then for wizards or witches such as Hermione, constant use might age them faster, adding days, weeks, or even months onto their internal chronological clock. It is also unknown how this applies to later on in life. If Hermione was perhaps a month older by using the Time-Turner during her third year, then biologically her seventeenth birthday might arrive a month earlier than her calendar birthdate might indicate, which might cause the Trace to have been lifted earlier as well.
- In LEGO Harry Potter: Years 1-4, there are grandfather clocks throughout Hogwarts which allow Hermione to use her Time-Turner to transport herself and her teammates back in time to complete certain objectives. One of these includes a mission where Harry and Hagrid hatch Norberta's egg.
- The Time-Turner is one of the many collectibles offered by the Noble Collection.
- Hermione Granger's Time-Turner is David Heyman's favourite prop from the films.
- You can hear quiet ticking as a background sound during nearly the whole Time-Turner episode of Harry Potter and the Prisoner of Azkaban (film).
- Harry Potter and the Prisoner of Azkaban (First appearance)
- Harry Potter and the Prisoner of Azkaban (film)
- Harry Potter and the Prisoner of Azkaban (video game)
- Harry Potter and the Order of the Phoenix
- Harry Potter and the Half-Blood Prince (Mentioned only)
- Harry Potter and the Cursed Child
- Harry Potter and the Cursed Child (play)
- LEGO Harry Potter
- LEGO Harry Potter: Years 1-4
- Harry Potter for Kinect (Mentioned and appears on a illustrative photograph)
- The Wizarding World of Harry Potter
- J. K. Rowling's Official Site
- Harry Potter: The Character Vault
Notes and references
- ↑ This quote comes from the "Harry Potter Sticker Kit", containing a plastic replica of the Time-Turner used on the film.
- ↑ Harry Potter and the Order of the Phoenix
- ↑ Blue Peter (CBBC) interview with JK Rowling, confirming that all the MoM time-turners were destroyed.
- ↑ Harry Potter and the Cursed Child, Act Four, Scene Four
- ↑ Harry Potter and the Cursed Child, Act Two, Scene Sixteen
- ↑ Harry Potter and the Cursed Child
- ↑ Assuming an average usage of 3 hours per day, 5 days per week, for a period of 9 months, this would add up to approximately 24 extra days.
- ↑ http://www.youtube.com/watch?v=e3FP-nmkFL0&feature=relmfu