A 19-inch rack is a standardized frame or enclosure for mounting multiple equipment modules. Each module has a front panel that is 19 inches (482.6 mm) wide, including edges or ears that protrude on each side which allow the module to be fastened to the rack frame with screws.

The 19-inch rack format has remained constant while the technology that is mounted within it has changed considerably and the set of fields to which racks are applied has greatly expanded. The 19-inch (482.6 mm) standard rack arrangement is widely used throughout the telecommunication, computing, audio, video, entertainment and other industries.

19-inch racks in 2-post or 4-post form hold most equipment in modern data centers, ISP facilities and professionally designed corporate server rooms. They allow for dense hardware configurations without occupying excessive floor space or requiring shelving.

The latest equipment rack is also designed to optimize thermal performance and cable management for high density server and network racks requiring exceptional air-flow. Cables are properly routed away from ventilation pathways. Door perforations are optimized to allow unobstructed ventilation paths to provide maximum airflow to equipments. Ducts direct hot exhaust air to the hot aisle to prevent reticulation into the inlet.