Bail, in law, the security or pledge given to a court to obtain the temporary release of a prisoner awaiting trial or appeal. The object is to prevent a person from being imprisoned before he has been proved guilty. The bail, in the form of money or property, may be provided by the prisoner or by a relative or friend. Bail may also be guaranteed by a bond—a promise to pay—usually from a professional bondsman or bonding company (who charges a fee equal to a percentage of the assigned sum). A person who "jumps" bail—does not appear for trial—is subject to immediate arrest, and the amount of bail is forfeited. A defendant who cannot “make" (get) bail must remain in jail until the trial, even though under United States law an accused person is presumed innocent until proved guilty.

The judge fixes the amount of bail, which varies according to the seriousness of the crime. (In some cases a judge can release a person whom he considers trustworthy on his “own recognizance"—that is, without bail.) “Excessive" bail is prohibited by the Eighth Amendment to the U.S. Constitution, but there is little agreement as to what amount is excessive. It is argued by many persons that a sum that is reasonable for a prosperous defendant is excessive for an impoverished one. In some cases, bail can be denied if there is reason to believe the defendant would flee before trial. Also, under the Bail Reform Act of 1984, a federal court can request “preventive detention" (detention prior to trial) if it decides that a suspect is a danger to the public.