Why did Hitler decide to commit suicide at the end of WW2 instead of surrendering to the Allied Powers?
Hitler finally recognized that all was lost and did not want to be taken captive and paraded through the streets of Moscow.
He had seen how the Italian people hung Mussolini in a public square and heaped humiliations upon his corpse. He definitely did not want to suffer that fate. He could do away with himself easily because he lacked respect for human life.
Because enemies were closing in on him from all sides, and there was no way to escape; he knew he had failed and had lost. He wasn't sure what they would do to him when they caught him, but knew it would probably be a life of torture, imprisonment and humiliation.
So he wanted a quick dignified death, and he wanted to die with honor with his beloved wife. So they took cyanide and had people shoot them, then his soldiers burned their bodies so their remains would not be desecrated.
The invading Soviet Army had reached Hitler in Berlin and he was close being captured. Supposedly, he was afraid of his body being humiliated post-mortem, like Mussolini's. Or he may have just been afraid. Hitler didnt want to be killed by Russians and had heard rumors that they would drag him around in a cage.
This is strictly an unverified rumor, or propaganda, depending upon whom you listen to. Many reliable eyewitness reports have him living to a ripe old age in Argentina.
He killed himself for many reasons; he knew he had lost, and he didn't want to hide or run, he did not want Stalin to capture him and parade him around as a war prize so Hitler killed himself and had his body cremated so not even that could be paraded. also, he killed himself because Soviet forces had surrounded Berlin and were closing in on his bunker. He believed that if he did get caught he would have a slow, painful and humiliating death, so he killed himself. He didn't want to be taken prisoner. Hitler had received reports of how Partisans executed Mussolini only 2 days earlier. They hung Mussolini's body in Milan to allow the angry mob to mutilate it. I think I've read that Hitler commented that he would not allow that to happen to him. Those are the reason that Adolph Hitler killed himself.
Because he had been defeated by Winston Churchill
An alternate answer - certainly favored by conspiracy theory lovers - is that we have no idea whether Hitler killed himself or not; he certainly did not cremate himself. Allied forces were halted outside Berlin for hours, when they might have captured Hitler; and a valid argument might be made that this was done so that Hitler could escape. America certainly inherited enough Nazi's at the end of the war to suggest this. There is more information in the book suggested in the link. It might be well to recognize that most everything we are taught about history in school is wrong; or at the very least written by the 'victors,' who have sufficiently outed themselves as liars, at this point, for one to seek the truth--whatever it may be--on their own.
When the Soviet troops entered Germany it was suggested that Hitler should try to escape. Hitler rejected the idea, as he feared the possibility of being captured. He had heard stories of how the Soviet troops planned to parade him through the streets of Germany in a cage. To prevent this humiliation Hitler decided to commit suicide. Two days before his death Hitler married Eva Braun. That night he tested out a cyanide pill on his pet Alsatian dog, Blondi. Braun agreed to commit suicide with him. She could have become rich by writing her memoirs but she preferred not to live without Hitler. Hitler made a will leaving all his property to the Nazi Party. After saying their farewells Hitler and Eva Braun went into a private room and took cyanide tablets. Hitler also shot himself in the head. His body was then cremated and his ashes were hidden in the Chancellery grounds. The place where he was buried is now under the shadow of the Berlin Wall. The man who tried to increase the size of Germany had in fact become responsible for dividing it into two. He had just heard how Benito Mussolini died. Mussolini was captured by partisans and executed and his body was hung up for public display and humiliation. Hitler said he didn't want anyone to find his body---that is why it was burned behind the bunker. He realized that the Russians would capture Berlin and he did not want to be captured and humiliated that's why he killed himself a.k.a (burned himself) He could not take the pressure of being defeated.