A panic bar (sometimes called a crash bar or a push bar) is a door locking device consisting of a spring-loaded metal bar fixed horizontally on the inside of an exit door roughly 40 inches up from the bottom of the door. When the panic bar is pushed, the latch releases and the door opens outward. This mechanism allows for a door to be opened quickly and easily when a panicked crowd presses against it in an emergency situation. Without a panic bar, a crowd may find it impossible to escape because the door would be too difficult to open inward. To serve its purpose effectively, this device must always open away from the side of the door on which the panic bar is mounted.

A panic bar can be used on single or double doors made of wood, steel, aluminum, or even glass. Typically, a door with a panic bar can only be opened from the inside, but when a panic bar is used on a two-way door, a different type of handle must be mounted on the outside.

Panic bars are required by law on all fire and emergency exits. The panic bar on a fire rated door must be able to withstand high temperatures and must latch every time the door closes. The panic bar on a non-fire rated door, on the other hand, may be temporarily unlocked by using a dog down key. When in this unlocked mode, the door can be opened by pulling or pushing on the door itself, not on the panic bar. Panic bars can also be found on chain link and decorative fence gates, particularly in large outdoor venues such as open air concert arenas and sports stadiums.

While a surface mount panic bar may be installed professionally, installation can also be completed by the ambitious do-it-yourselfer. Many different types of standard and deluxe panic bar kits with comprehensive installation instructions are available for purchase. These kits include all necessary mounting hardware, fasteners, adjustable receiving latches, and optional lock boxes for outside keyed or card accessed entry.