Why does Hamlet kill Claudius?

Hamlet kills Claudius to avenge his father’s murder, but the act comes only after a long struggle over whether revenge is morally justified at all. The ghost of Hamlet’s father tells him that Claudius murdered him by pouring poison into his ear while he slept, then stole both his throne and his wife. Hamlet immediately vows revenge, yet throughout the play he delays taking action because he is consumed by doubt, fear, and philosophical questions about death, justice, and sin.

Hamlet’s hesitation comes from more than cowardice. He worries about whether the ghost can be trusted and whether killing Claudius would damn his own soul. Even after he confirms Claudius’s guilt through the staged play meant to “catch the conscience of the king,” he still can’t act decisively. When he finds Claudius alone and praying, Hamlet refuses to kill him because he fears Claudius’s soul might go to heaven. Hamlet wants revenge to feel meaningful and just, yet the Christian beliefs surrounding sin, repentance, and the afterlife make revenge feel morally tangled rather than heroic.

By the final act, however, Hamlet’s thinking has changed. After seeing death everywhere around him, especially in the graveyard scene with Yorick’s skull, he becomes more fatalistic. He tells Horatio, “There is a special providence in the fall of a sparrow [...] The readiness is all.” Hamlet stops trying to control every moral consequence of his actions and accepts that death comes for everyone.

Claudius’s final plot against Hamlet pushes him into action. During the duel with Laertes, Hamlet learns that Claudius has arranged both the poisoned sword and the poisoned wine that kills Gertrude. Laertes confesses “the king’s to blame,” and Hamlet finally acts without hesitation. He stabs Claudius with the poisoned sword and forces him to drink the poisoned wine, killing him just as Claudius poisoned Hamlet’s father. The revenge is immediate, violent, and reciprocal.

Shakespeare presents Hamlet’s revenge as tragic rather than triumphant. Hamlet succeeds in killing Claudius only after nearly everyone around him has died, including Gertrude, Laertes, and Hamlet himself. The play treats revenge as something that spreads corruption and death through the entire kingdom rather than restoring true justice.