Albus Dumbledore is the most powerful wizard in the Harry Potter. Dumbledore seemed like a lovely older man and the Headmaster of Hogwarts who only wanted the best for everyone when Harry first met him.
Documents in the wizarding world suggest that Merlin was one of the most powerful wizards in Harry Potter and human history in general. Merlin was a Slytherin at Hogwarts and demonstrated an amazing understanding of the magical arts. Some argue him to be the most powerful wizard of all time.
He may be the titular character, but Harry is far from the most powerful wizard in the wizarding world. Sure, he does eventually go on to take down the greatest dark wizard of all time, but his success comes more as a result of his mother's sacrifice and the support of his friends than it does his own brilliance.
Dumbledore may have been a legendary wizard, but he can't be compared to, well, Merlin, a wizard so legendary even Muggles know of his exploits. Merlin was the world's most famous wizard, and, arguably, the world's most powerful.
1 Voldemort – Harry Potter
He who should not be named makes the number one spot. Voldemort is known for his viciously evil nature. He has wiped out entire generations of Wizards for standing against him, and his power in the dark arts knows no equal.
He was the most accomplished at Legilimency. No one could prevent Voldemort from looking inside their mind. Expect Snape. This shows Severus' abilities against the Dark Lord, making it clear that Severus was the more superior of the two.
Harry himself is a half-blood, since his pure-blood father, James, married a Muggle-born witch named Lily, and his maternal grandparents were Muggles.
While most fans agree that Harry is the unrefuted Chosen One, the final Deathly Hallows film (in particular) sways heavily toward highlighting a heroic Neville, revitalizing the debate regarding which boy is better suited for the iconic title. "The one with the power to vanquish the Dark Lord approaches ...
Lord Voldemort (Ralph Fiennes), aka Tom Riddle, was described by Dumbledore as one of the best students ever to graduate Hogwarts as well as "the most dangerous Dark wizard of all time." Before he had even learned about the existence of the Wizarding world, he was terrorizing his fellow orphans with impressive but ...
1. Albus Dumbledore. Image via Warner Bros.
Merlin was supposed to be so strong as a wizard (Yes, more powerful than Dumbledore), many thought him to be a legend. He is, although, believed to have attended Hogwarts school and was apparently in Slytherin (which is why the Order of Merlin has a green ribbon).
Even when battling Voldemort, in Harry Potter and the Order of the Phoenix, Dumbledore never uses lethal magic. In the duel, Dumbledore is definitely on par with Voldemort, and Voldemort is seen to be annoyed that he can't overpower Dumbledore.
Harry is incredibly, natively powerful. He can perform advanced magic at an early age at greater levels than we see done by any other wizard (for example when he blasts the dementors away with his Patroness in the third book).
The most powerful PURE BLOODS are NOT the most powerful wizards- in fact, a top 10 list for the most powerful wizards would only include a couple of the people in this list. The majority of powerful witches and wizards in the wizarding world are actually HALF-BLOODS.
Draco Lucius Malfoy (b. 5 June, 1980) was a pure-blood wizard and the only son of Lucius and Narcissa Malfoy. The son of a Death Eater, Draco was raised to believe strongly in the importance of blood purity. He attended Hogwarts School of Witchcraft and Wizardry from 1991-1998 and was sorted into Slytherin House.
So, had Snape gone all out in the duel against McGonagall in Deathly Hallows, she would have put up a good fight, but he would have prevailed in the end due to his edge in the Dark Arts, Legilimency and Occlumency.
House-elves could perform magic beyond that of a wizard
Dobby frequently demonstrated himself to be immensely powerful, causing Lucius Malfoy himself to back down with just a point of his finger.
Without a doubt, the most powerful wizard in Middle-earth is Gandalf the White. While Gandalf was always a reasonably powerful wizard in his own right, facing off against the Balrog in the Mines of Moria, a battle that took ten days and resulted in the mutual demise of Gandalf and the Balrog.
Lord Voldemort
Tom Marvolo Riddle started both Wizarding Wars, created the Death Eaters and killed Harry Potter's parents. We could go on – he was the most dangerous Dark wizard of all time – but we won't. His horrific achievements are well known.