It is never stated.
Hogwarts exists only in the Harry Potter series.
The Hogwarts gamekeeper (also known as the Hogwarts groundskeeper) is a Wizard employed by Hogwarts School of Witchcraft and Wizardry to tend to and look after the grounds of the school, as well as the security of Hogwarts Castle. It is Rubeus Hagrid.
Harry Potter's school is called Hogwarts School of Witchcraft and Wizardry. In the fourth book, Hogwarts hosts the triwizard tournament and students from two other schools come to compete. These schools are Beauxbatons Academy of Magic and Durmstrang Institute.
Hogwarts was founded in the 9th or 10th century, an exact date is unknown.
it will probably take centuries
they need money to rebuild and i do not konw
3years?
about 2 years
it took about a year and a half
about 13 years
Bout 2 minutes
2 seconds
about 13 years
1-2 years
See: Atomic bombings of Hiroshima and Nagasaki.
The estimate is about 15 years.