In Fahrenheit 451, at what temperature does paper catch fire?

In Fahrenheit 451, paper is said to catch fire at 451 degrees Fahrenheit.

Ray Bradbury used the figure as the title of his 1953 dystopian novel. The book’s title page describes 451°F as the temperature at which book paper catches fire and burns. Bradbury reportedly asked about paper’s ignition point and was given this figure, which became an especially memorable symbol of the novel’s world of firemen who burn books.

The number is a literary shorthand rather than a universal physical constant. Actual ignition depends on paper composition, thickness, moisture, airflow, and exposure time; scientific estimates can fall in a broader range, often around the mid-400s Fahrenheit. That distinction sometimes causes confusion, but within the novel’s context, 451°F is the canonical answer.

Another common mix-up is 212°F, the boiling point of water at sea level. Fahrenheit 451 is not claiming that every sheet of paper ignites at exactly the same instant at that temperature; it is presenting a striking title premise tied to censorship, knowledge, and cultural control.